Chapter M: G. Vaiden writes to me that he found a nest near Belzoni, Miss., in a (3)

"Although a number of wood warblers which winter in the Central American highlands are gregarious, those that center in the lowlands are typically solitary. In this, the yellow warbler is no exception. Each wintering bird appears to have its own territory, from which it attempts to drive others of its kind. Trespassers are scolded with insistent _chips_; or more rarely, soon after his arrival, a male will sing while defending his claim. Near San Miguel de Desamparados, Costa Rica (4,600 feet), on October 1, 1935, I made the following note: 'This morning, which for a change was bright and calm, I heard a yellow warbler singing in the low fig trees near the house. Upon going out to look, I found that there were two yellow warblers in the trees. One was trying to drive the other away; but the pursued always circled around and returned. I watched them for a long time; but this indecisive action continued without any change in the situation. In the intervals of the pursuit, the warblers (or at least one of them) would sing, but in a low and imperfect fashion, far inferior to the yellow warbler's summer song.' Again, on October 31: 'After the Wilson warbler, the most abundant winter visitor is the yellow warbler. The bird who on October 1 drove its competitor out of the fig trees beside the house still retains these trees and the surrounding _Inga_ trees as its domain.'

"The yellow warbler sings far less while in Central America than many other wintering species. Exceptionally, one will be found singing profusely. In early October, 1934, I came upon such a bird among the coffee groves of a great plantation on the lower Pacific slope of Guatemala. His behavior was so far out of the ordinary that I am tempted to copy in full the notes I made upon it at the time: October 5--On the afternoon of my arrival at 'Dolores,' I went out for a walk through the coffee groves. From among the 'chalum' (_Inga_) trees which shaded the coffee bushes, I heard a bird's song which seemed to belong to a warbler; but I did not recognize it as the utterance of any species I knew. After searching for a time among the tree-tops, I spotted the singer, and was surprised to find him a yellow warbler. He was apparently a young bird, for he lacked the chestnut splashes along the sides which distinguish the mature males. He repeated over and over again his little song of four or five notes, which was so unlike the familiar song of the yellow warbler in the eastern United States that I did not at first recognize it; but once I had identified the singer, I realized that I was listening to a shortened and modified form of the typical song.

"As I stood watching and listening to this eccentric warbler, the rain clouds which had been gathering darkly in the west began to surrender their pent-up waters; and the sudden shower approached across the plantation with the roar of a myriad fat drops striking against the large leaves of the Ingas and the far larger ones of the bananas which shaded the plantation. I took refuge from the rain beneath the broad expanse of a banana leaf, which completely shielded me from the beating downpour. Soon the heavy shower exhausted itself; and I emerged from beneath my green roof. The warbler, who had taken shelter from the shower somewhere in the foliage above me, resumed his cheerful singing.

"'On the next two days, I passed by the spot where I had heard the warbler singing, on the way to and from my botanical collecting ground. Morning and afternoon, I heard the same voice in the same part of the coffee plantation, where the bird seemed to have fixed his residence.'

"Yellow warblers may sing in Central America in the spring as well as the fall. Last year, the male yellow warbler that wintered about my house in Costa Rica sang briefly in the early morning from April 12 to 24. After April 28, I saw no more of his kind in the vicinity.

"From November 1936 until February of the following year, a yellow warbler slept every night in a bush of _Hibiscus mutabilis_ beside my cabin in Rivas, Costa Rica. He rested upon one of the long leaf-stalks, where the broad blades of the higher leaves formed a roof above him, but he was exposed on the sides and easily visible from the ground. He always slept alone.

"Early dates of fall arrival in Central America are: Guatemala--passim (Griscom), August 9; Sierra de Tecpán, 8,500 feet, September 4, 1933; Huehuetenango, 6,500 feet, September 11, 1934. Honduras--Tela, August 14, 1930. Costa Rica--Puerto Limón, August 17, 1935; San José (Cherrie), August 24; Cartago, September 6, 1938; Basin of El General, 2,000-3,000 feet, September 13, 1936 and September 11, 1942. Panamá--Canal Zone (Arbib and Loetscher), August 22, 1934.

"Late dates of spring departure are: [British Guiana (Beebe), April 10.] Panamá--Barro Colorado Island, April 23, 1935; Almirante, April 29, 1929. Costa Rica--Basin of El General, April 30, 1936, April 29, 1937, May 7, 1939, May 3, 1940, April 28, 1942; San José (Cherrie), May 11. Honduras--Tela, May 9, 1930. Guatemala--passim (Griscom), May 6; Los Amates, Motagua Valley, May 11, 1932."

Todd and Carriker (1922), reporting for the Santa Marta region of Colombia, say that the eastern yellow warbler is "a common winter resident throughout the whole of the lowlands and lower foothills, but rare above the coastal plain. It frequents shrubbery, open ground with scattering bushes, the low growth along the banks of streams and the sea-beach, etc.--the same kind of covert in general to which it is so partial in the breeding season."

DISTRIBUTION

_Range._--North America, northern South America and the West Indies.

_Breeding range._--The yellow warblers of North America breed =north= to north-central Alaska (Kobuk River and Fort Yukon); northern Yukon (Potato Creek, 20 miles above Old Crow River); northwestern Mackenzie (Richard Island, Fort Anderson, Lake St. Croix, and Oot-sing-gree-ay-Island, Great Slave Lake); northern Manitoba (Lac Du Brochet, Churchill, York Factory, and Severn House); and central Quebec and Labrador (Richmond Gulf, Grand Falls of the Hamilton River, probably Northwest River, and Cartwright). =East= to eastern Labrador (Cartwright); Newfoundland (St. Anthony, Twillingate, and St. John's); Nova Scotia (Cape Breton Island, Halifax, and Yarmouth); and the Atlantic coastal region south to eastern and central North Carolina (Pine Island, Lake Mattamuskeet, Raleigh, and Charlotte); central South Carolina (Columbia); and central Georgia (Augusta and Macon). =South= to central Georgia (Macon); central Alabama, rarely (Autaugaville); southern Arkansas (Monticello and Arkadelphia); northeastern Texas (Paris, Commerce, and Dallas); west-central Oklahoma (Fort Reno and Thomas); southern New Mexico (Roswell and Silver City); probably southwestern Texas (Fort Hancock and El Paso); northern Sonora (Moctezuma, Magdalena, and Colonia Indepencia); and northwestern Baja California (El Rosario). =West= to the Pacific coast from northern Baja California (El Rosario) to western Alaska (Frosty Peak, Alaska Peninsula; Nushagak, Hooper Bay, Saint Michael, and Kobuk River). Wandering birds have been collected at Icy Cape and Wainwright on the northwest coast of Alaska several hundred miles north of the northernmost breeding record.

_Winter range._--The yellow warbler is found in winter =north= to southern Baja California (La Paz); Jalisco (La Barca); Morelos (Cuernavaca and Yautepec); southern Veracruz (Tlacotalpan); Yucatán (Tunkás); and Quintana Roo (Akumal); occasional or accidental in winter near Brownsville, Tex. =East= to Quintana Roo (Akumal); Honduras (Tela and Ceiba); Nicaragua (Bluefields); Panamá (Almirante and the Canal Zone); Venezuela (Trinidad Island); British Guiana (Georgetown and the Berbice River); Surinam (Paramaribo); Cayenne (Cayenne and Approuague); and northeastern Brazil (Chaves). =South= to northern Brazil (Chaves, and Bôa Vista on the Rio Branco) and central Perú (La Merced). =West= to central western Perú (La Merced); western Ecuador (Guayaquil, Chones, and Esmeraldas); western Colombia (Condoto, Medellín, and Turbo); western Costa Rica (El General, San José, and Bolson); El Salvador (Puerto del Triunfo); western Guatemala (San José and Matzantinango); Chiapas (Huehuetán); Guerrero (Coyuca); Colima (Manzanillo); and southern Baja California (La Paz).

The range as outlined is divided into several subspecies or geographic races. The Newfoundland warbler (_D. p. amnicola_) breeds from central western Alaska south to central British Columbia, central Alberta, Saskatchewan and Manitoba, central Ontario and Quebec northward and east to Newfoundland; the Alaska yellow warbler (_D. p. rubiginosa_) breeds in the coastal region of southern Alaska; the Rocky Mountain yellow warbler (_D. p. morcomi_) breeds from southern British Columbia and Washington east through the Rocky Mountains south to northern Nevada, northern Utah and northern New Mexico; the California yellow warbler (_D. p. brewsteri_) breeds west of the Sierras in Oregon and California; the Sonora yellow warbler (_D. p. sonorana_) breeds from southeastern California, southern Nevada, and southern New Mexico to northwestern Mexico and western Texas; the eastern yellow warbler (_D. p. aestiva_) breeds from southern Canada east of the Rocky Mountains southward. The Cuban golden warbler (_D. p. gundlachi_) which is resident in Cuba, the Isle of Pines, and adjacent Cays has been found nesting on Bay Key, Fla. The mangrove, or "golden," yellow warbler (_D. p. castaneiceps_) breeds on both coasts of Baja California from about latitude 27° 14´ N. (San Lucas) southward; and on the west coast of Mexico from southern Sonora (Guaymas) south to Nayarit (San Blas). (Apparently it is only slightly migratory, if at all.)

_Migration._--Early dates of spring departure are: Perú--Iquitos, March 11. British Guiana--Abary River, March 25. Venezuela--Rancho Grande, April 8. Colombia--Santa Marta Region, May 1. Panamá--Canal Zone, May 12. Costa Rica--San José, May 11. El Salvador--Chilata, April 24. Guatemala--Quiriguá, May 11. Honduras--Tela, May 9. Mexico--Tabasco, Balancán, May 11; Nuevo León, Montemorelos, May 21. Florida--Seven Oaks, May 27. Mississippi--Deer Island, May 25. Louisiana--Chenier au Tigre, May 21. Texas--Kerrville, May 31.

Early dates of spring arrival are: Florida--Pensacola, April 6. Georgia, Athens, April 7. South Carolina--Charleston, April 3. North Carolina--Windsor, April 4. Virginia--Lawrenceville, April 13. District of Columbia--Washington, April 2. Pennsylvania--Wayne, April 4. New York--New York, April 19. Massachusetts--Taunton, April 24. Vermont--Burlington, April 28. Maine--Portland, May 2. New Brunswick--Scotch Lake, May 1. Nova Scotia--Wolfville, May 8. Quebec--East Sherbrooke, May 6. Prince Edward Island--North River, May 6. Newfoundland--St. Anthony, June 5. Louisiana--Avery Island, March 23. Mississippi--Shell Mound, April 1. Arkansas--Tillar, April 5. Kentucky--Eubank, April 12. Indiana--Richmond, April 14. Ohio--Oberlin, April 12. Michigan--Ann Arbor, April 19. Ontario--London, April 20. Missouri--St. Louis, April 15. Iowa--Cedar Rapids, April 20. Wisconsin--Reedsburg--April 27. Minnesota--Minneapolis, April 27. Texas--Victoria, March 28. Oklahoma--Stillwater, April 16. Kansas--Topeka, April 16. Nebraska--Red Cloud, April 21. South Dakota--Faulkton, April 22. Manitoba--Aweme, April 30. Saskatchewan--Regina, May 4. Arizona--Fort Lowell, March 19. New Mexico--Albuquerque, April 24. Utah--Provo, April 25. Colorado--Littleton, April 23. Montana--Fortine, May 1. Alberta--Camrose, May 3. Mackenzie--Simpson, May 21. California--Diablo, March 12. Oregon--Portland, April 17. Washington--Camas, April 5. British Columbia--Comox, April 25; Atlin, May 15.

Late dates of fall departure are: Alaska--Ketchikan, September 6. British Columbia--Atlin, August 26; Chilliwack, September 9. Washington--Destruction Island, September 23. Oregon--Newport, September 18. California--Berkeley, October 10. Alberta--Edmonton, September 1. Montana--Great Falls, September 25. Wyoming--Yellowstone National Park, September 21. Colorado--Fort Morgan, October 2. Arizona--Organ Pipe Cactus National Monument, October 17. Saskatchewan--East End, September 5. Manitoba--Oak Lake, September 18. North Dakota--Fargo, September 19. South Dakota--Aberdeen, September 20. Kansas--Hays, September 23. Texas--Somerset, October 8. Minnesota--Lanesboro, September 10. Wisconsin--Milwaukee, September 20. Iowa--Marshalltown, September 26. Missouri--Bolivar, October 26. Michigan--Grand Rapids, October 8. Ontario--Ottawa, September 29. Ohio--Cleveland, September 30. Illinois--Chicago, September 29. Kentucky--Hickman, September 23. Mississippi--Gulfport, October 20. Louisiana--New Orleans, October 27. Newfoundland--Tompkins, September 9. Quebec--Montreal, September 3. New Brunswick--St. John, September 2. Nova Scotia--Yarmouth, September 11. Maine--Winthrop, September 23. Vermont--St. Johnsbury, September 21. Massachusetts--Stockbridge, October 1. New York--Rochester, October 30. Pennsylvania--Berwyn, October 7. District of Columbia--Washington, October 12. Virginia--Lexington, October 10. South Carolina--Charleston, October 10. Georgia--Milledgeville, October 27. Florida--Fort Myers, October 25.

Early dates of fall arrival are: Louisiana--New Orleans, July 15. Mississippi--Bay St. Louis, July 7. Florida--St. Marks, July 18. Mexico--Sonora, Sáric, July 31; Oaxaca, Tapanatepec, August 20. Honduras--Lancetilla, August 27. El Salvador--Le Unión, August 1. Nicaragua--Bluefields, August 22. Costa Rica--Puerto Limón, August 17. Panamá--Almirante, August 13. Colombia--Bonda, Santa Marta Region, August 27. Venezuela--Cantaura Anzoatique, September 27. British Guiana--Abary River, September 2. Surinam--Paramaribo, August 28.

_Banding._--The majority of the banding recoveries indicate the return to the place of banding and give records of longevity. Three birds banded as adults at Wilton, N. Dak., were retrapped at the same station in the following year. One banded at Sioux City, Iowa, on May 17, 1929, was killed by an auto at the same place June 18, 1932. One banded at Sault Ste. Marie, Mich., on May 30, 1926, was retrapped on May 29, 1929; another banded at the same station, May 20, 1928, was killed by an auto June 28, 1934. A yellow warbler banded at North Eastham, Cape Cod, Mass., on May 28, 1931, was retrapped at the same station May 15, 1932, May 18, 1936, and August 6, 1937.

_Casual records._--The yellow warbler has twice been collected in Bermuda: November 23, 1875; and October 14, 1903. It has also been observed near Habana, Cuba, on September 3 and 10, 1939. There are three winter records in South Carolina; it was seen at a feeding station at Summerville in the winter of 1939 and on January 21, 1940; and at Charleston on January 18, 1947.

_Egg dates._--California: 110 records, April 16 to July 15; 56 records, May 21 to June 19, indicating the height of the season.

Massachusetts: 113 records, May 19 to June 30; 82 records, May 27 to June 7.

Minnesota: 26 records, May 29 to June 23; 17 records, May 29 to June 8.

New Jersey: 32 records, May 15 to June 24; 24 records, May 26 to June 7.

Utah: 23 records, May 8 to July 16; 12 records, June 6 to 17.

Washington: 21 records, May 28 to June 24; 11 records, June 2 to 7.

Baja California: 11 records, May 8 to June 12; 6 records, May 15 to June 2, indicating the height of the season.

Mexico: 6 records, June 4 to 20 (Harris).

DENDROICA PETECHIA AMNICOLA Batchelder

NEWFOUNDLAND YELLOW WARBLER

HABITS

Based on a series of 14 adult males and 3 adult females from Newfoundland, Charles F. Batchelder (1918) gave the above name to the yellow warblers that breed in that region. After giving a detailed description of the type from Curslet, Newfoundland, he remarks: "When seen in series, the yellow of the under parts is duller, less richly golden, and the chestnut streaks are darker. In comparison with _aestiva_, the female is duskier, less yellowish, throughout the upper parts. * * *

"In general coloring _D. ae. amnicola_ shows a certain similarity to _D. ae. rubiginosa_, but it is readily distinguishable from that race by the yellow forehead which, as in _D. ae. aestiva_, contrasts strongly with the green of the back."

Its breeding range extends from Newfoundland to central Alaska, and from Nova Scotia to British Columbia, which includes nearly all of Canada. It migrates through most of the United States, principally through the Mississippi River Basin, and winters in Mexico and possibly South America.

Only a few nesting data are referable to the Newfoundland yellow warbler. Henry Mousley (1926), at Hatley, Quebec, saw a female yellow warbler leaving a large cedar hedge, and says: "Proceeding to the spot from which she came out, I found the nest, which, unlike the usual run of nests of this species, was heavily lined with feathers, instead of plant down. * * * It was nine feet above the ground, in the forks of a small cedar tree."

Roderick MacFarlane (1908) found this warbler abundant in northern Mackenzie, where the nests were "placed on dwarf willows and small scrub pine at a height of a few feet above the ground." Dr. E. W. Nelson (1887) writes:

This is, perhaps, the most abundant warbler throughout Alaska. It is found everywhere in the wooded interior, on the bushy borders of the water-courses, or frequenting the scattered clumps of stunted alders on the shores of Bering Sea, and the coast of the Arctic about Kotzebue Sound. * * * It breeds to the shores of the Arctic Ocean wherever it can find a willow or alder patch wherein to build its nest and shelter its young. * * * In fall, from the last of July to towards the last of August, they come about the houses and native villages to feast on the fare they find provided abundantly in those localities, until, a little later in the season, a few chilling storms send them trooping away with others of their kind to far distant winter quarters.

Dr. Herbert Brandt (1943) writes:

The Newfoundland Yellow Warbler was not observed about Hooper Bay, but as soon as I reached the willows near the mouth of the Yukon River I found it common, and also of like distribution at the other stops that I made on the river as far up as Mountain Village. * * *

The nest of the Newfoundland Yellow Warbler in the Yukon delta is placed usually in a small willow from two to six feet above the ground. The foliage in early July is but partly unfolded, for the alders are yet in their golden curls and the willows in their silver catkins, so the nest is rather conspicuous.

The bird chooses a pronged fork usually with not more than three or four shoots, and in this form constructs its beautiful, trim nest, which is made of plant down and inner bark shreds, all circularly woven and firmly rimmed.

Baird, Brewer, and Ridgway (1874) say: "The notes of Mr. Kennicott and the memoranda of Messrs. McFarlane, Ross, and Lockhart attest the extreme abundance of this species in the farthest Arctic regions. In nearly every instance the nests were placed in willows from two to five feet from the ground, and near water. In one instance Mr. Ross found the eggs of this species in the nest of _Turdus swainsoni_, which had either been deserted or the parent killed, as the eggs were in it, and would probably have been hatched by the Warbler with her own."

As evidence of the late migration of this subspecies, Robie W. Tufts writes to me from Nova Scotia: "The latest date of departure which appears to be normal is October 7, 1936, though they generally leave during the second week of September. On November 25, 1929, a female was collected by me at Wolfville. The bird was searching for food very actively and its general behavior was decidedly abnormal. The bird's body showed slight traces of emaciation." Birds that have been recorded in Massachusetts as late as September 30, long after our local breeding birds have left, were probably of this subspecies.

DENDROICA PETECHIA RUBIGINOSA (Pallas)

ALASKA YELLOW WARBLER

HABITS

This subspecies was formerly supposed to range throughout most of Alaska, but its breeding range is now understood to be restricted to the coast region of southern Alaska and British Columbia, from Kodiak Island (the type locality) southward to Vancouver Island. It migrates through California to Mexico and Central America, and probably spends the winter in South America. In El Salvador, according to Dickey and van Rossem (1938), "this race was found only as a fairly common spring migrant through the upper levels of the Arid Lower Tropical. As with _D. p. aestiva_ the winter range undoubtedly lies farther to the south. It is notable that _rubiginosa_ occurs at somewhat higher elevation than the other three forms and was not found at all in the 'tierra caliente.'" This race has been reported in Kansas and in central Texas, but these birds may have been _amnicola_, which somewhat resembles _rubiginosa_ and which had not been accepted at that time.

Ridgway (1902) describes the Alaska yellow warbler as "similar to _D. ae. aestiva_, but slightly smaller and much duller in color. Adult male darker and duller olive-green above, the pileum concolor with the back or else becoming slightly more yellowish on forehead (very rarely distinctly yellowish on forehead and fore part of crown); wing-edgings less conspicuous, mostly yellowish olive-green, sometimes inclining to yellow on greater coverts. Adult female darker and duller olive-greenish above, duller yellow below." He might have added that the chestnut streaks on the breast are narrower than in _aestiva_.

Nothing seems to have been published on the nest and eggs of the Alaska yellow warbler, nor on its habits, all of which probably do not differ materially from those of the species elsewhere in similar environment.

DENDROICA PETECHIA MORCOMI (Coale)

ROCKY MOUNTAIN YELLOW WARBLER

HABITS

This is another race that was described many years ago by H. K. Coale (1887) but has only recently been accepted by the A. O. U. Coale gave it its scientific name in honor of J. Frean Morcom and called it the western yellow warbler. The following remarks by Dickey and van Rossem (1938) tell the story very well:

The race of yellow warbler summering in the Great Basin and Rocky Mountain regions of the United States of late years has been generally overlooked and has been synonymized commonly with _aestiva_ or, in part, with _brewsteri_. Although not a well differentiated form, its characters are readily apparent in series, and there is no reason why it should not be accorded equal standing with the races currently recognized. The underparts of the males are heavily marked, and in this respect _morcomi_ is not distinguishable from _aestiva_. Dorsally, however, _morcomi_ is darker and less yellowish green, particularly on the interscapular region. The females are, age for age, more buffy (less yellowish) below and darker and more grayish above than the females of _aestiva_. In comparison with _brewsteri_, _morcomi_ (particularly the bill) is larger, and the males are more heavily streaked below. The range of _morcomi_ is the Rocky Mountain region of the United States, north to Wyoming and Idaho, west to the eastern slope of the Sierra Nevada, and south (in the western part of its range) to Mammoth, Mono County, California. We have not seen material from the southern Rocky Mountains; so we cannot state the southern limits in that region.

They call it a "common spring and fall migrant and winter visitant in the lowlands," of El Salvador. "Dates of arrival and departure are August 1 and April 9."

Angus M. Woodbury has sent me a copy of the manuscript for "The Birds of Utah," by Woodbury, Cottam, and Sugden, from which I infer that the haunts, nesting, and other habits of the "western yellow warbler," as they call it, do not differ materially from those of the well-known eastern bird. They say of its status in Utah: "This yellow warbler is a common summer resident from early May to late August, the vanguard sometimes reaching here in late April and stragglers sometimes lingering into September, the latest record being September 23. It is primarily a bird of the riparian growths along water edges, either of streams, ponds or lakes or irrigated areas, particularly of the valleys and lower canyons, but occurs higher in the canyons in suitable habitat up to at least 8,000 or 9,000 feet. It does not seem to be attracted to large trees such as cottonwoods, but seems to prefer the more leafy shrubbery and small trees of developmental stages in ecological succession. In migration, it sometimes leaves this niche and may occasionally be found elsewhere. * * *

"In nesting, it is usually found in a bush, chaparral or small tree stratum, seldom going to the ground or to the tops of trees. Its nests are compactly woven cups generally placed from 3 to 10 feet above ground, sometimes 15 feet, in rosebushes, willows, choke cherries, hawk-berries, oaks, young cottonwood or boxelder trees, usually within a short distance of the water's edge. The nest is usually composed of gray plant fibers, bark shreds or grasses and is usually lined with some downy substance such as cottonwood or willow cotton or hair."

DENDROICA PETECHIA BREWSTERI Grinnell

CALIFORNIA YELLOW WARBLER

HABITS

The 1931 A. O. U. Check-List gives the breeding range of this subspecies as the "Pacific coast strip from western Washington south through Oregon and California, west of the Great Basin and southeastern deserts to about lat. 30° in Lower California." It intergrades with _rubiginosa_ on the north and with _morcomi_ to the eastward, but exact boundaries are difficult to define. It seems to range well up into the mountains, for James B. Dixon tells me that he has found it nesting in Mono County, Calif., at altitudes of 6,500 to 9,200 feet.

Dr. Joseph Grinnell (1903) in an interesting study of western yellow warblers, bestowed the above name on the California bird, for which he gives the following subspecific characters: "Resembling _Dendroica aestiva aestiva_, from which it differs in smaller size, paler (or less brightly yellow) coloration, and, in the male, narrower streaking on under surface; differs from _Dendroica aestiva rubiginosa_ in much smaller size and yellower coloration, and from _Dendroica aestiva sonorana_ in smaller size and much darker coloration."

_Spring._--Both _rubiginosa_ and _brewsteri_ occur in California and in Washington on migrations. As it is difficult to distinguish the two forms in life, some of the following remarks may refer to either or both of these two subspecies. Mrs. Amelia S. Allen writes to me that this species "is the latest of the warblers to arrive in the San Francisco Bay region for the breeding season. Sometimes they are here by April 8, but the average date is about April 18. At Lake Tahoe, the first week of June, breeding pairs were settled in the willows and migrants on their way farther north were migrating through."

Samuel F. Rathbun says in his Washington notes: "Our experience with this species, based on many years of observation, is that the birds in the spring migration progress northward in a series of what may be called waves. Invariably the first noted will be one or two individuals, and these are heard for a short time only and evidently move on. Then there is a break of a day or so before the next are heard, a larger number. A period of a day, or perhaps two or three, may again elapse before the main body of birds arrive and they are heard on all sides. Common in and about the city at this period, it haunts the shade trees lining the streets and the fruit trees in the gardens, but is not at all partial to the outlying sections, except in the more cultivated areas and the orchards. It is essentially a bird of the older settled districts, wherever fruit trees and deciduous trees may abound."

For May 6, 1924, he remarks, "These warblers drifted by all day, in ones and twos or threes, straggling, but, although seemingly widely separated, always within hearing distance of each other. At times there will be a break when apparently none are passing, then in the distance the song will be heard again, soon growing louder, as the bird draws nearer, following in the wake of others that have preceded him, his song in turn growing fainter in the distance after he has passed."

_Nesting._--The summer haunts and nesting habits of the California yellow warbler are generally similar to those of the eastern bird. Grinnell and Storer (1924) write:

Yellow warblers nest abundantly on the floor of Yosemite Valley. Some of the nests are in growths close to water, whereas others are located in brush tangles or other rank growths back some distance from the streams. A nest found June 7, 1915, may be taken as fairly typical. It was 52 inches above the ground in the crotch of a forking stem of a chokecherry which grew in a clump of the same plant, and was shaded by a black oak. As usual it was higher than wide outside, being 3-1/2 inches in height by 3 to 3-1/4 inches in diameter. The cuplike cavity was 1-3/4 inches across at the top and the same in depth at the center. Shreds of bark and flat plant fibers were the principal materials used in construction, the lining being of horsehair and a few feathers.

One nest was "4 feet above the ground in a mountain lilac (_Ceanothus integerrimus_)," and another "was placed about 15 feet above the ground in a small pine tree growing at the margin of a pond. It rested on the next to the topmost whorl of branches and one side was against the slender trunk of the tree."

In the Lassen Peak region, Grinnell, Dixon, and Linsdale (1930) report four nests in willows, one in a wax-berry (_Symphoricarpos_), one in a snowbush, and one fastened between stems of rose and willow at the edge of a clump of rose.

_Eggs._--Three or four eggs seem to constitute the commonest set for the California yellow warbler. These are hardly distinguishable from those of the eastern bird, though they average, perhaps, more heavily marked. The measurements of 40 eggs average 16.6 by 12.4 millimeters; the eggs showing the four extremes measure =18.3= by 13.5, 17.8 by =15.0=, =14.7= by 12.2, and 16.3 by =11.4= (Harris).

_Food._--Prof. F. E. L. Beal (1907) analyzed the contents of 98 stomachs of California yellow warblers, and found that the animal matter amounts to 97 percent of the food, consisting wholly of insects and a few spiders.

The largest item is Hymenoptera, which amounts to over 30 percent, almost half of which are ants. The remainder are small bees and wasps, some of which are probably parasitic species, though none were positively identified. * * * Caterpillars, with a few moths, aggregate over 18 percent.

Beetles form nearly 16 percent of the diet, and embrace about a dozen families, of which the only useful one is that of the ladybirds (_Coccinellidae_), which are eaten to a small extent. The great bulk of the beetle food consists of small leaf-beetles (_Chrysomelidae_), with some weevils and several others. One stomach contained the remains of 52 specimens of _Notoxus alamedae_, a small beetle living on trees. Bugs (Hemiptera) constitute over 19 percent of the food, and are eaten regularly every month. Most of them consist of leaf-hoppers (Jassidae) and other active forms, but the black olive scale appeared in a number of stomachs. Plant-lice were not positively identified, but some stomachs contained a pasty mass, which was probably made up of these insects in an advanced stage of digestion.

Flies seem to be acceptable to the summer warbler; they are eaten to the extent of nearly 9 percent. Some of them are of the family of the house fly, others are long-legged tipulids, but the greater number were the smaller species commonly known as gnats. A few small soft-bodied Orthoptera (tree-crickets), a dragon-fly, and a few remains not identified, in all about 5 percent, made up the rest of the animal food.

Only about 2-1/2 percent of the food was vegetable matter, made up mainly of fruit pulp in a single stomach, one or two seeds and rubbish.

Rathbun (MS.) says that this warbler "shows some partiality for feeding on aphids, for we have many times watched it in an orchard carefully scanning the leaves on a tree for this insect."

All other phases of the life histories of this and the following two subspecies do not seem to differ materially from those of the eastern yellow warbler and need not be repeated here.

_Fall._--According to Rathbun's notes, all the resident, breeding yellow warblers have departed from Washington "by the latter part of August, and in some seasons we have not heard the bird after the twenty-fifth; it is one of the few species that sing more or less during all of its sojourn here, and its song in late summer is almost as good as on its arrival in the spring. A break in the movement south of this species seems to occur about August 20 to 25. Then, early in September, the notes of the yellow warbler begin to be heard again. We have the idea that these may be of the Alaska yellow warbler."

Mrs. Allen writes to me from Berkeley, Calif.: "Breeding birds leave the bay region in late July or early August; migrants from farther north begin to go through in September; the latest date on which I have seen them is October 16, 1920. I usually see them in the shade trees along the streets or in the woods when they come to bathe in my bird pool. But I have two records which show them in very different situations: September 18, 1933, on a hill slope that had been recently burnt over, a group of these warblers with horned larks and Savannah sparrows; and on September 25, 1941, at Point Reyes lighthouse, hunting for food in the low, dry lupines just inside the rocky point. One could not help wondering if they had just come to a landing place after a long flight over the ocean. They were in immature plumage."

According to the 1931 Check-List, the California yellow warbler "migrates through eastern California, Arizona, and Lower California; winters sparsely in the Cape District of Lower California and south to Guatemala, Nicaragua, and Costa Rica."

_Winter._--Dickey and van Rossem (1938) record this warbler as a "winter visitant and spring migrant in the Arid Lower Tropical Zone," in El Salvador. "The small Pacific coast race, _brewsterii_, is apparently relatively the least common of the four forms found in El Salvador; at any rate, the small number of specimens taken indicates that this is the case. Yellow warblers were common in January at Puerto del Triunfo and in February at Rio San Miguel, but unfortunately only one specimen was taken at each place. Whether all of these winter birds were _brewsteri_ and _morcomi_ is problematical."

DENDROICA PETECHIA SONORANA Brewster

SONORA YELLOW WARBLER

HABITS

This is the palest of all the yellow warblers, one of the many pale races of the southwestern desert regions. Its breeding range extends from southeastern California, southern Utah, Arizona, and New Mexico to central western Texas, Sonora, and Chihuahua; and it winters from Mexico southward to Guatemala, Nicaragua, and Costa Rica.

It is best described by Ridgway (1902) as "similar to _D. æ. æstiva_, but much paler; adult male lighter and much more yellowish olive-green above, the back frequently (usually?) streaked with chestnut, pileum usually wholly clear yellow, lower rump and upper tail-coverts yellow, faintly streaked with olive-greenish; wing edgings all yellow; under parts lighter yellow than in _D. æ. æstiva_, and with chest and sides much more narrowly (often faintly) streaked with chestnut; adult female conspicuously paler than in _D. æ. aestiva_, the upper parts often largely pale grayish, the under parts usually very pale buffy yellow."

Woodbury, Cottam, and Sugden (MS.) say of its status in southern Utah: "This race of yellow warbler is a breeder of the streamside fringes of willows, tamarix, and brush of various kinds along the San Juan and lower Colorado Rivers. It undoubtedly extends up the Colorado above the mouth of the San Juan, but how far it extends before yielding to _morcomi_ has not been determined. Data available are not sufficient to determine its nesting or migration dates or the length of its stay in Utah."

Swarth (1914) calls it "a common summer visitant in southern and western Arizona, apparently confined almost entirely to the Lower Sonoran river valleys, the Colorado and the Gila, with their tributaries. * * * I know of no breeding record of a yellow warbler from any point in Arizona north of the Mogollon Divide." Mrs. Bailey (1928) says that "the lower Rio Grande in New Mexico apparently marks the most northern extension of the range of the Sonora Yellow Warbler. It is a common breeder at Mesilla," which is in the southwestern part of the State.

We found the Sonora yellow warbler breeding commonly in the San Pedro Valley, near Fairbank, Ariz., and found several nests in a row of willows along an irrigation ditch. The nests, from 12 to 15 feet above the ground in slender trees, were not very different from those of the eastern bird, being made mainly of willow cotton interwoven with fine strips of inner bark, fine grasses, and plant fibers.

The eggs do not differ greatly from those of the species elsewhere, though what few I have seen are more faintly and finely speckled. The measurements of 40 eggs average 16.9 by 12.8 millimeters; the eggs showing the four extremes measure =18.4= by 13.1, 17.0 by =13.6=, =14.9= by 12.5, and 17.8 by =11.4= millimeters (Harris).

DENDROICA PETECHIA GUNDLACHI Baird

CUBAN YELLOW WARBLER

HABITS

The Cuban yellow warbler was originally described by Baird (1864) as a full species but is now regarded as a subspecies of _Dendroica petechia_. Ridgway (1902) describes it as "similar to _D. p. petechia_, but duller in color; adult male with upper parts much darker olive-green, the pileum usually concolor with the back, sometimes slightly more yellowish, very rarely tinged with orange-ochraceous, and wing-edgings less purely yellow; adult female usually duller in color than in _D. p. petechia_, often grayish olive-green, or even largely gray, above, and dull whitish, merely tinged here and there with yellow, beneath."

Until recently, its range has been supposed to include only Cuba and Isle of Pines. Dr. Barbour (1923) says of its habits: "The Mangrove Canary, as the Cuban Yellow Warbler is called, is abundant wherever there are heavy high mangroves about the coast. I have found it abundant in eastern and western Cuba, and on the Isle of Pines as well. Gundlach reports it nesting in March. I incline to believe that May is more usual; and then the nest of grass, small feathers and woolly down, is placed in a fork on some horizontal mangrove limb. The whole life of the species is passed in the mangrove forests."

Referring to the Isle of Pines, W. E. C. Todd (1916) writes: "This is a bird of the mangroves, to which it is apparently exclusively confined. It is accordingly most numerous along the coast and about the islands of Siguanea Bay, where the mangroves are so constant and pronounced a feature. Mr. Read has observed it along the Pine River also, but it is apparently a rare bird in the northern part of the island, judging from the dearth of records, and, indeed, it cannot be called a common bird in any locality as yet visited. Two nests were found, both in mangroves within a few feet of the water, during the third week in April, but as yet without eggs."

More recently, this warbler has been found breeding on some of the lower Florida Keys. Earle R. Greene (1942) writes:

While exploring one of the Bay Keys in the Great White Heron National Wildlife Refuge off Key West, Florida, on June 15, 1941, with Roger Tory Peterson of the National Audubon Society, a male warbler, in full song, was located. * * * On June 26, the writer located it again on the same key, and on the 28th the male, female and nest were found. The last was in the top part of a red-mangrove tree (_Rhizophora mangle_) and was composed of seaweed and feathers; it contained one egg, white with brownish markings chiefly about the larger end. On July 10, the egg was found broken, apparently jabbed, possibly by a Red-wing nesting nearby. On July 16, the male bird was collected, and on the 30th the female.

Later (1944) he says: "Since then, a male and female were seen on June 16, 1942, on these same keys, and on July 14, 1942, an adult female was noted on the same keys. On August 6, 1942, a male and female, as well as an immature bird, being fed by an adult, were found on Big Mullet Key in the Key West Refuge, which is several miles from the Bay Keys. A letter received from Mrs. Frances Hames states that she found one bird, in song, on one of the Bay Keys on May 30, 1943. I consider it, therefore, a regular nester on certain keys in that area. Additional investigations may determine it as a common breeder."

DENDROICA PETECHIA CASTANEICEPS Ridgway

MANGROVE YELLOW WARBLER

HABITS

Along both coasts of Baja California southward from about latitude 27° N., and along the Pacific coast of Mexico from Sinaloa to Guatemala, where that curious tree, the red mangrove (_Rhizophora mangle_), bathes its feet in salt water along the shores of bays, estuaries, and tidal creeks, this handsome yellow warbler makes its permanent home. The red mangrove extends its growth on these muddy shores by sending its curving branches outward and downward to take root again in the mud, thus forming an almost impenetrable tangle of roots and branches in an ever-widening band extending outward from the dry land. Its dense, dark foliage forms a low, gloomy forest of branches in which this well-named warbler finds a secure retreat and to which it is almost exclusively confined. It has not always been easy to obtain in these tangles, for Brewster (1902) says that--

during January, February, and a part of March, 1887, Mr. Frazer repeatedly visited all the mangrove thickets that he could find near La Paz, and made every effort to secure a good series of these Warblers, but he took only eight in all and did not shoot more than a pair in any one day. He notes the bird as "rare," but adds that "its numbers Increased slightly in March." It cannot be very numerous here at any time, for the total area covered by its favorite mangroves is very limited. Indeed, the place where most of his specimens were obtained "comprises only about two acres, through which winds a small creek, fordable at low tide; but at high water everything is submerged up to the lower branches of the mangroves. I always found the birds working near the surface of the water on the stems of the mangroves or hopping about on the mud, but the males resorted to the tops of the bushes to sing. Their notes are similar in general character to those of the Yellow Warbler."

W. W. Brown was evidently more successful a little later in the season, for, in that same locality in May and June, he collected a large series of these beautiful birds for several American collections, mainly Col. John E. Thayer's. He wrote to Colonel Thayer (1909):

I found the Mangrove Warbler a rare bird, but my previous experience with this species in Panamá, the Pearl Islands, and in Yucatan is what made me successful. I learned its song and alarm note in 1893. The first morning I went into the mangrove swamps of La Paz I whistled the song of the Yucatan species and the birds answered me; this is the secret of my success, for the species is very secretive in its habits. I found it so difficult to get that I offered fifty cents apiece to the duck hunters and others, including the local taxidermist, but they all failed to get it! By covering eight miles of territory I generally managed to get four or five. Sometimes when I shot one It would fall in the mangroves, with a tide running fast. Under such conditions it generally took a long time to find it, and a great deal of cutting with the machete.

Referring to the form found in El Salvador, Dickey and van Rossem (1938) remark: "To add to the difficulties in the path of the collector, the brown and yellow plumage of the males blends perfectly with the dead or dying mangrove leaves which are kept in continual motion by the sea breeze."

_Nesting._--Brown sent Colonel Thayer (1909) three nests of the mangrove warbler, only one of which contained a set of three eggs. Of this he says: "The nest with eggs is made (and the others resemble it very much) of light green fern down, cobwebs, and light-colored dried grasses, with a few white feathers plastered on the outside. It is beautifully lined with feathers. It is not so perfectly shaped or so well made as the Yellow Warbler's nest."

There are now six beautiful nests of this warbler in the Thayer collection in Cambridge, all collected by Brown near La Paz on dates ranging from May 15 to June 2; all were placed in the red mangroves, either on horizontal branches, mostly near the ends, or in forks; the heights from the ground or water varied from 2 feet to 10 feet. The largest and handsomest nest was 10 feet up on a horizontal branch; it is a very neat, compactly woven cup, made of soft, fine, light buff plant fibers, mixed with plant down, green moss that looks like down (probably the "light green fern down" referred to above or _algae_), a few gray lichens and many whitish flower clusters; it is lined with very fine fibers, apparently from the mangroves, and plenty of feathers; it measures externally 3 inches in diameter and 2-1/2 inches in height; the inner diameter at the top of the in-curved rim is 1-3/4 inches and the cup is near 2 inches deep. The smallest nest measures only 2-1/4 inches in outside diameter. The shallowest nest is only 1-1/2 inches high and 1-1/4 deep inside.

These nests are all works of art and quite distinctive; all the materials are smoothly and compactly felted, being tightly plastered together, as if glued on when wet. The light color and compactness suggest certain hummingbirds' nests. Most of the nests seem small for the size of the birds.

_Eggs._--Three eggs seems to form the usual set for the mangrove warbler; in the Thayer series there are five sets of three and one set of two. Ed. N. Harrison (MS.) says that "it seems that one egg is a set as often as two." Most of the eggs in this series are ovate, but some are short ovate; they have only a very slight gloss. They are white or creamy white, speckled, spotted or blotched with shades of "mummy brown," "bone brown," "Prout's brown," or "clove brown," with undertones of "light mouse gray," "deep mouse gray," "Quaker drab," or "drab-gray." The browns are frequently so dark as to appear almost black, but some eggs are spotted with lighter shades, such as "cinnamon brown" and "snuff brown." On the more lightly marked types the most prominent markings are the grays, with only a few scattered brown spots. Often a loose wreath is formed around the large end, where the spots are usually concentrated.

The measurements of 32 eggs average 17.9 by 13.4 millimeters; the eggs showing the four extremes measure =19.5= by 13.2, 17.9 by =14.6=, =17.0= by 13.2, and 18.3 by =12.9= millimeters (Harris).

_Plumages._--Although I have examined a large series of mangrove warblers, I have seen no downy young and no summer birds in juvenal plumage. But Dr. Chapman (1907) describes the young female as "above grayish olive-green, rump brighter; tail blackish, externally greenish, webs of all but central narrowly margined with yellow; wings and their coverts blackish, quills margined, coverts tipped with dull greenish; below whitish more or less washed or obscurely streaked with yellow, the under tail-coverts pale yellow."

Young males in the fall are much like adult females, but brighter in color and often with traces of chestnut on the head. Apparently young males wear this femalelike plumage all winter; young males in March show a variable amount of chestnut on the head and throat, and show further progress toward maturity during April, May, and June, indicating a first prenuptial molt. A specimen described by Brewster (1902) is apparently undergoing this molt. "It has the head dull chestnut, very pale and mixed with whitish on the throat, mottled with greenish on the crown; the jugulum, sides of the neck and the middle of the breast _white_ with occasional small patches or single feathers of a pale yellow color and numerous fine, chestnut-rufous streaks on the breast; the remainder of the under parts pale primrose yellow mixed with whitish. The back, wings, and tail are nearly as in the adult female. The upper mandible is of the usual dusky horn color, but the basal half of the lower mandible of a pale flesh color. The plumage, generally, has a worn and faded appearance."

This would seem to indicate that the first prenuptial molt is quite extensive, and that young birds become nearly adult after their molt. Adults probably have a complete postnuptial molt sometimes during the summer, but the following descriptions indicate that the prenuptial molt of adults is less extensive. Ridgway (1885) describes the type male, taken December 16, 1882, as follows: "Head rich chestnut, lighter or more rufous on the throat. Upper parts olive-green, the wings dusky, with broad greenish yellow edgings; outer webs of rectrices dusky, edged with yellowish olive-green, the inner webs chiefly primrose-yellow. Lower parts bright gamboge-yellow, the jugulum and breast with a few very indistinct and mostly concealed streaks of chestnut-rufous." And of an adult female, taken December 29, 1882, he says: "Above grayish olive-green; wings grayish dusky, the feathers edged with olive-grayish; rectrices dusky, outer webs edged with olive-green, the inner with primrose yellow. Lower parts dull pale olive-yellowish."

From Dr. Chapman's (1907) descriptions of spring adults it appears that there is very little seasonal change. Male: "Head all around and throat reddish chestnut; back yellow olive-green, the rump brighter; inner webs of all but central tail feathers largely yellow; wings black margined with yellow; underparts, except throat, rich yellow faintly streaked with reddish brown." Female: "Above olive green, much darker and greener than [M]; tail black the two outer feathers with large yellow patches on the inner web near the tip; wings black margined with greenish yellow; below uniform pale, dull yellow."

Laurence M. Huey (1927), referring to the bird life of San Ignacio and Pond Lagoons, on the west coast of Baja California, states that mangrove warblers were found there--

in isolated pairs and gave evidence of early nesting by their singing and by the condition of the sex organs of the specimens collected. This warbler was one of the most interesting species observed. The song of the male was usually delivered from a hidden position amid the dense mangroves, though occasionally the bird was seen perched on a dry twig projecting above the level tops of the thicket. The song was pleasing in tone, and of good volume, suggesting that of the Yellow Warbler, but less shrill. Unlike the song of the Yellow Warbler, it was given with a steady rising inflection. The alarm note is a sharp chirp, audible at some distance even during a brisk wind. This note is uttered at intervals and always in the same tone, much as are the chipping notes of the Orange-crowned Warblers. In searching for food, Mangrove Warblers resemble others of the genus _Dendroica_ in their habit of searching each leaf and stem with most careful scrutiny. At times, however, they were seen to launch forth into the air, in true "flycatcher" fashion, after small insects. These aerial sallies were seldom for a distance of over 10 feet, and the bird nearly always returned to the same perch from which it started.

_Enemies._--The following remarks by Dickey and van Rossem (1938) about the El Salvador race of this species are of interest:

As the entire lives of these birds are spent in an environment which renders them immune from attack by the great majority of the predators which harass species inhabiting the land forest, one is at first inclined to be surprised at their relative scarcity. Raccoons (_Procyon_) are extremely common in the mangroves and were often found prowling through the branches at night. They, as well as carnivorous iguanas, undoubtedly take toll of many nests, but aside from these two it is difficult to conjecture what natural enemy operates to limit the mangrove warbler population. Certainly no "saturation point" has been reached, for pairs may be separated by as much as a mile even in the areas which appear most favorable.

DENDROICA MAGNOLIA (Wilson)

MAGNOLIA WARBLER

PLATES 26-28

HABITS

Wilson secured only two specimens of this pretty warbler, one of which was shot among some magnolia trees near Fort Adams, Miss. He gave it the scientific name _Sylvia magnolia_ but called it the black and yellow warbler. This stood for many years as the common name. Nuttall, who had seen it only occasionally in Massachusetts, regarded it as rare. Audubon, on the other hand, found it quite common and even abundant in several places, as we now know it to be. His lively plate of this beautiful bird, one of his best, has always been a favorite of mine; and it seems to me that in the magnolia warbler, more than in any one of the many beautiful species of American wood warblers, are best combined daintiness of attire with pleasing combinations and contrasts of often brilliant colors. Particularly are these qualities apparent when this warbler is seen amongst the dark green firs and spruces of its summer home, where its brilliant array of colors are displayed to advantage as it flits about, sometimes within a few feet of us.