Part 32

_Fall._--The myrtle warbler is one of the latest of its family to move southward and is also one of the most leisurely in migration; the migration covers practically the whole of September and October and much of November, the earliest arrivals sometimes reaching the Gulf States before the last ones have left Canada. Abundant in the spring, it is much more so in the fall, when it can often be seen in enormous numbers. As the birds drift along southward, many stop along the way where food is abundant and some spend the winter at no great distance from the southern limits of the breeding range. In Massachusetts, we usually look for them during the latter half of September or during those golden October days when woods are ablaze with the gorgeous autumn colors. As we stroll along the sunny side of the woods on some bright morning after a frosty night, the air is full of pleasing bird music. The robins, now wild woodland birds, are twittering or uttering their wild autumn calls as they drift through the trees; the white-throated and the song sparrows, from the brushy thickets below, give forth their faint, sweet notes like soft echoes of their springtime songs; and the myrtle warblers mingle their distinctive call-notes with these other voices as they glean for aphids on the birches. In the open grassy fields and weed patches, too, we find many myrtle warblers associated with the scattered flocks of juncos and field and chipping sparrows, feeding on the ground. And later in the fall, we find them in the bayberry patches near the seacoast, or even on the salt marshes or among the sand dunes with the Ipswich and savanna sparrows.

Southward along the Atlantic coast the flight is heavy; Dr. Stone (1937) says that, at Cape May, N. J., "on October 13, 1913, Julian Potter encountered a great flight of Myrtle Warblers which he estimated at 3,000. * * * October 31, 1920, was a characteristic Myrtle Warbler day. All day long they were present in abundance. The air seemed full of them wherever one went. Thousands were flittering here and there in the dense growth of rusty Indian grass (_Andropogon_), in the bayberry thickets, in pine woods and in dune thickets."

From their breeding grounds in the northern interior these warblers continue to drift southward during October, not in compact flocks but straggling in a continuous stream, some alighting while others are moving on. In Ohio, according to Trautman (1940), "the numbers continued to increase rapidly until approximately October 5. Between October 5 and 20 the species was more numerous over the entire land area than it was at any other season, and thousands were daily present. It was particularly abundant on Cranberry Island, where it fed upon insects, cranberries, poison sumac, and other berries. On several occasions an estimated number between 1000 and 1200 individuals was seen within an hour on this island. After October 20 there was a rather gradual decline in numbers. By November 1, comparatively few remained, and in some years the birds had disappeared."

_Winter._--The myrtle warbler winters abundantly throughout the southern half of the United States east of the Great Plains, commonly as far north as southeastern Kansas, southern Illinois, southern Indiana and northern New Jersey, and less commonly or rarely and irregularly farther north. It is the only one of the wood warblers that is hardy enough to brave the rigors of our northern winters amid ice and snow and sometimes zero temperatures.

Robert Ridgway (1889) writing of its winter habits in southern Illinois, says:

It may often be sees in midwinter, when the ground is covered with snow, in the door-yards along with Snowbirds (_Junco hyemalis_), Tree Sparrows, and other familiar species, gleaning bread crumbs from the door-steps, or hunting for spiders or other insect tidbits in the nooks of the garden fence or the crevices in the bark of trees; and at evening, flying in considerable companies, to the sheltering branches of the thickest tree tops (preferably evergreens), where they pass the night. Not infrequently, however, they roost in odd nooks and crannies about the buildings, or even in holes in the straw- or hay-stacks, in the barn-yard. A favorite food of this species are the berries of the Poison-vine (_Rhus toxicodendron_), and during the early part of winter large numbers of them may be seen wherever vines of this species are abundant.

What few myrtle warblers remain in southern Massachusetts are usually to be found in situations similar to those frequented in late fall, especially near the coast where there is a good supply of bayberries and other berries. When this supply is exhausted they move elsewhere, though they can subsist to some extent on the seeds of the pitch pine, on grass seed, and on various weed seeds. In New Jersey, they are found in similar situations. Farther south they are abundant inland as well as on the coast, living in all kinds of environments--old fields, cultivated lands, thickets, brushy borders of the woodlands, and in woods of scrub oaks and pine. They are common to abundant on both coasts of Florida and in the interior and often come into the orange groves, to feed on the fallen oranges. A. H. Howell (1932) says: "Not infrequently they may be found in numbers on the Gulf beaches, or in reeds in the salt marshes of the coast or in the Everglades. They are partial to the borders of streams or sloughs, and sometimes venture out on the floating vegetation in rivers or lakes."

The following is contributed by Dr. Alexander F. Skutch: "In December, 1932, it was vividly brought home to me how widely the myrtle warblers are spread over the earth during the winter months, and in what varied climates they dwell. On the ninth, a clear, cold, winter day, I met a small party of these yellow-rumped birds in a barren field at the edge of a woods in Maryland. On the twenty-fourth, I watched them fly above the tatters of melting snow in New Jersey, within view of the skyscrapers of New York. That afternoon I embarked upon a ship, and a week later arrived upon a banana plantation in Guatemala, where the air was balmy and the landscape vividly green, where snow and bleak winds seemed to belong to another world. Yet here, too, were myrtle warblers, hundreds of them, feeding in the open pastures and along the roadways, wherever the vegetation was not too dense, then rising up in compact flocks, wheeling and dropping together, moving always as though actuated by a true group spirit. During three days on that plantation, I met 23 kinds of winter visitants from the North; yet the myrtle warbler appeared to be the most abundant of them all: certainly, I saw far more of them than of any other migratory bird; yet this was in part because they foraged in more exposed places. Of all the warblers I found here, this was the only species that moved in flocks; for most of the wood warblers that winter in the Central American lowlands are strict individualists. It is also significant that of all the 23 species of wintering birds, this, the most abundant in December, was the only one then common that I had not recorded from February to June of the same year, when I passed 4 months studying the birds on that same plantation.

"Although it has been recorded from Central American localities as early as October and as late as April, the myrtle warbler is certainly most abundant as a winter visitant from November to March. All my own records from points in Guatemala, Honduras, and Costa Rica fall within these 5 months. It arrives later and departs earlier than warblers less tolerant of cold.

"The myrtle warbler winters in a variety of situations. At Puerto Castilla, on the northern coast of Honduras, I found these warblers abundant at the end of January, 1931. Here they foraged upon the lawns between the cottages, hopping rather than walking like water-thrushes, and when alarmed flew up to rest upon the broad fronds of the coconut palms that lined the sandy beach. At the other extreme, I have found them in mountain pastures, rarely as high as 8,500 feet above sea level. In the highlands, this bird is likely to be confused with the Audubon warbler, from the mountains of western United States, in similar dull winter attire. But the Audubon warbler, even at this season, wears five patches of yellow--on the crown, throat, both sides and rump--while the myrtle warbler shows only four, lacking that on the throat. The presence or absence of yellow on the throat is a distinguishing feature.

"At the end of December, 1937, I found myrtle warblers abundant in the vicinity of Buenos Aires de Osa, a hamlet in the lower Térraba Valley of Costa Rica, of interest to the bird-watcher because, although lying in a region covered by the heaviest lowland forest, it is surrounded by extensive open savannas which support a rather different bird-life. Here fork-tailed flycatchers were also abundant, roosting by night in some orange trees behind the padre's house, by day spreading in small flocks over the savannas, where they perched in the low bushes, only a few feet above the ground, and darted down to snatch up the insects they descried. It was surprising to find the myrtle warblers associating intimately with the flycatchers; just as, in the Guatemalan highlands, I had found Audubon's warblers flocking with bluebirds. The myrtle warblers not only foraged about the bushes which served the flycatchers as watch-towers; but the two kinds of birds, so dissimilar in size and habits, changed their feeding grounds together. While I sometimes found the warblers alone, I saw them in company with the fork-tailed flycatchers too often for the association to be looked upon as accidental. I could not discover that either warbler or flycatcher derived any material advantage from the presence of the other. It seemed to be a case of pure socialibility.

"Central American dates are: Guatemala--Motagua Valley, near Los Amates, December 31, 1932; Sierra de Tecpán, March 16, 1933; Finca Mocá, January 20-26, 1935; Nebaj (Griscom), April 27; La Primavera (Griscom), April 8. Honduras--Puerto Castilla, January 27, 1931; Tela (Peters), March 17. Costa Rica--Vara Blanca, December 13, 1937, to February 28, 1938; Guayabo (Ridgway and Zeledón), March 18; Carrillo (Underwood), October 2; Guacimo (Carriker), December 4; Las Cañas, Guanacaste, November 21, 1936; El General, January 12, 1936; Buenos Aires de Osa, December 24-30, 1937."

DISTRIBUTION

_Range._--North America.

_Breeding range._--The myrtle warbler breeds =north= to northern Alaska (Kobuk River and timberline on the south slope of the Brooks Range); northern Yukon (La Pierre House); northern Mackenzie (Aklavik; Fort Anderson; MacTavish Bay, Bear Lake; Lake Hardisty, and Artillery Lake); northern Manitoba (Lac du Brochet, Cochrane River, and Churchill); northern Ontario (Moose Factory); southern Labrador (Grand Falls and Rigolet, possibly Nain and Okkak). =East= to eastern Labrador (Rigolet and Cartwright); Newfoundland (St. Anthony, Canada Bay, and St. John's); and Nova Scotia (Cape Breton Island, Sable Island, Halifax, and Yarmouth). =South= to southern Nova Scotia (Yarmouth); New Brunswick (Grand Manan); southern Maine (Gouldsboro, Deer Isle, Bath, and Auburn); New Hampshire (Concord); central and southern Massachusetts (Marlboro, Webster, and Pelham); southwestern Vermont (Bennington); northern New York (Falls Pond and Buffalo); rarely northeastern Pennsylvania (Pocono Lake); accidentally in northern Maryland (Havre de Grace); southern Ontario (London and Sarnia); northern Michigan (Crawford County and Douglas Lake); northern Wisconsin (Antigo, probably, Trout Lake, Namekagon Lake, and Superior); central Minnesota (St. Cloud, Brainerd, and Bemidji); southern Manitoba (Winnipeg and Aweme); central Saskatchewan (Flotten Lake and Prince Albert); central Alberta (Flagstaff, Camrose, Lobstick River, and Wipiti River); northern British Columbia (Fort St. John, Ingenika River, and Buckley Lake); and southern Alaska (Admiralty Island, Sitka, Seldovia, and Nushagak). =West= to western Alaska (Nushagak, Russian Mission, St. Michael, and the Kobuk River).

_Winter range._--The myrtle warbler winters in two discontinuous areas. The principal winter home is =north= to central Oklahoma (Oklahoma City); northern Arkansas (Winslow, Little Rock, and Helena); western Tennessee (Memphis); southern Illinois (Anna and Mount Carmel); southern Kentucky (Bowling Green); central Virginia (Lexington); District of Columbia (Washington); southeastern Pennsylvania (Philadelphia); northern New Jersey (Morristown and Elizabeth); southern Connecticut (New Haven); Rhode Island (Providence); and northeastern Massachusetts (Cape Ann). It also occurs in winter irregularly =north= to Holly, Colo.; Hays and Manhattan, Kan.; Madison, Wis.; Chicago, Ill.; Battle Creek and Rochester (one banded in January), Mich.; Rochester, N. Y.; and Portland, Maine. =East= to Massachusetts (Cape Ann) and along the Atlantic coast to Florida (Miami and Key West); the Bahama Islands (Little Abaco and Caicos); Dominican Republic (Puerto Plato and Sánchez); Puerto Rico (San Juan); St. Croix Island; and rarely, Antigua. =South= to Antigua, northern Colombia, rare or accidental (Santa Marta region); and Panamá (Pearl Islands). =West= to Panamá (Pearl Islands, Canal Zone, and Almirante); Costa Rica (El General and Guayabo); eastern Nicaragua (Greytown and the Río Escondido); northern Honduras (Puerto Castilla and Lancetilla); western Guatemala (Dueñas and Tecpán); eastern Oaxaca (Tehuantepec); Veracruz (Orizaba); Tamaulipas (Victoria); Nuevo León (Monterrey); southwestern Texas (mouth of the Pecos River, Camp Barkeley, Taylor County, and Fort Worth); and central Oklahoma (Oklahoma City).

The western winter range is =north= to central Western Oregon (Newport and Albany). =East= to western Oregon (Albany); central California (Marysville, Stockton, Mariposa County, Redlands, and Potholes); southern Arizona (Tucson and Tombstone); and southwestern Sonora (Guaymas). =South= to southern Sonora. =West= to western Sonora (Guaymas and the Colorado River delta); western California (San Clementi Island, Santa Barbara, San Francisco Bay region, and Eureka); and western Oregon (Coss Bay and Newport).

The species as outlined is divided into two subspecies or geographic races. The Alaska myrtle warbler (_D. c. hooveri_) breeds from western Alaska and northwestern Mackenzie to central Alberta and central British Columbia; the eastern myrtle warbler (_D. c. coronata_) from western Saskatchewan eastward.

_Migration._--Late dates of spring departure from the winter home are: Costa Rica--Guayabo, March 18. El Salvador--Volcán de San Miguel, March 22. Guatemala--Nebaj, April 27. Honduras--Lancetilla, March 17. Mexico--Valles, San Luis Potosí, May 2. Puerto Rico--Mayagüez, April 8. Haiti--Port-au-Prince, April 27. Cuba--Habana, April 28. Bahamas--New Providence, April 2. Florida--Pensacola, May 13. Alabama--Birmingham, May 8. Georgia--Atlanta, May 20. South Carolina--Greenwood, May 12. Louisiana--Mansfield, May 2. Mississippi--Oxford, May 8. Tennessee--Nashville, May 17. Arkansas--Helena, May 18. Texas--Bonham, May 6. Oklahoma--Norman, May 3.

Early dates of spring arrival are: New York--New York, April 1. Massachusetts--Lynn, April 11. Vermont--St. Johnsbury, April 12. Maine--Portland, April 6. New Brunswick--Scotch Lake, April 11. Nova Scotia--Yarmouth, April 11. Quebec--Hatley, April 22. Newfoundland--St. Anthony, April 25. Labrador--Cartwright, May 24. Illinois--Chicago, March 24. Indiana--Bloomington, March 26. Ohio--Youngstown, April 1. Ontario--Harrow, April 3. Michigan--Sault Ste. Marie, April 9. Missouri--Columbia, March 27. Iowa--Sigourney, April 3. Wisconsin--New London, April 1. Minnesota--Minneapolis, April 4. Kansas--Independence, April 7. Nebraska--Red Cloud, April 1. South Dakota--Brookings, April 7. North Dakota--Fargo, April 13. Manitoba--Aweme, April 12. Saskatchewan--Eastend, April 22. Mackenzie--Simpson, May 7. New Mexico--San Antonio, April 18. Colorado--Colorado Springs, April 17. Wyoming--Laramie, April 15. Montana--Kirby, April 29. Alberta--Glenevis, April 14. Washington--Seattle, March 14. British Columbia--Courtenay, March 31; Atlin, April 21. Yukon--Sheldon Lake, April 26. Alaska--Wrangell, April 29; Fairbanks, May 7.

Late dates of spring departure of transients are: District of Columbia--Washington, June 1. Pennsylvania--Warren, June 6. Illinois--Chicago, June 3. Indiana--Waterloo, June 3. Ohio--Oberlin, May 31. Missouri--Concordia, May 25. Iowa--Grinnell, June 1. Nebraska--Nenzel, May 27. North Dakota--Argusville, May 30. California--Red Bluff, May 3. Nevada--Quinn River Crossing, May 21. Washington--Tacoma, May 3.

Late dates of fall departure are: British Columbia--Atlin, September 19; Courtenay, October 14. Mackenzie--Nahami River, October 25. Wyoming--Laramie, November 25. Saskatchewan--Yorkton, October 14. Manitoba--Brandon, October 31. North Dakota--Argusville, November 15. South Dakota--Faulkton, November 15. Kansas--Lawrence, November 12. Minnesota--St. Paul, November 5. Wisconsin--Racine, November 16. Iowa--Wall Lake, November 15. Missouri--Kansas City, November 16. Illinois--Murphysboro, November 21. Michigan--Detroit, November 19. Indiana--Indianapolis, November 20. Ontario--Point Pelee, November 23. Ohio--Toledo, November 17. Newfoundland--Tompkins, October 4. Prince Edward Island--North River, October 15. Quebec--Kamouraska, November 9. New Brunswick--Saint John, November 4. Maine--Portland, November 9. New Hampshire--Durham, November 4. Massachusetts--Boston, November 27. New York--Brooklyn, November 22. Pennsylvania--Doylestown, November 29.

Early dates of fall arrival are: Washington--Bellingham, September 28. Oregon--Thurston, October 5. California--Eureka, October 12. Wyoming--Yellowstone Park, August 25. North Dakota--Fargo, September 8. South Dakota--September 15. Nebraska--Fairbury, September 30. Kansas--Lawrence, September 26. Oklahoma--Oklahoma City, October 12. Texas--Somerset, October 10. Iowa--Grinnell, September 6. Missouri--St Louis, September 17. Illinois--Chicago, August 31. Indiana--Hobart, September 2. Ohio--Austinburg, August 25. Kentucky--Bowling Green, September 14. Tennessee--Athens, October 3. Arkansas--Rogers, October 4. Louisiana--Monroe, September 26. Mississippi--Edwards, September 22. New York--Rhinebeck, August 31. Pennsylvania--Pittsburgh, September 8. District of Columbia--Washington, September 9. West Virginia--Bluefield, September 12. Virginia--Naruna, September 22. North Carolina--Mount Mitchell, September 30. South Carolina--Spartanburg, September 21. Georgia--Round Oak, October 10. Alabama--Anniston, October 8. Florida--New Smyrna, October 4. Bahamas--Cay Lobos, November 22. Cuba--Habana, November 17. Dominican Republic--San Juan, October 1. Puerto Rico--Mayagüez, December 14. Costa Rica--Carrillo, October 2.

_Banding._--The myrtle warbler comes rather more readily than other warblers to banding traps, especially in winter, and so has yielded several records of migration and of longevity for return to the place of banding. A myrtle warbler banded at Elmhurst, Long Island, on October 19, 1936, was recovered on December 9, 1936, at Awensdaw, S. C. One banded on October 2, 1932, at Fargo, N. D., was found dead December 5, 1932, at Clarence, La. Another banded at Wilton, N. D., on September 25, 1939, was found in January 1940 at Leola, Ark. One banded on February 2, 1930, at Gastonia, N. C., was shot on December 25, 1930, at Kings Creek, Cherokee County, S. C.

A banding station at Thomasville, Ga., obtained several records indicative of the birds' tendency to return to the same wintering place. Three birds banded in March 1920, were retrapped in February and March of 1921. One banded February 24, 1921, was retrapped February 5, 12, and 13, 1924, and found dead, apparently of starvation, on the fifteenth. A myrtle warbler banded on February 28, 1917, was retrapped in March 1920 and several times between March 1 and 17, 1921. It was then at least 5 years old and had made four round trips to the breeding grounds.

Another myrtle warbler banded at Huntington, Long Island, on October 23, 1933, was killed February 1, 1940, at Dunbar, S. C.; it was then at least 6-1/2 years old.

_Casual records._--At least six specimens of the myrtle warbler have been collected in Greenland: Fiskenaes, May 21, 1841; Julianehaab, about 1847; Godhavn, July 31, 1878; Nanortalik, May 23, 1880; Agpamiut, in Sukkertoppen District, October 15, 1931; and Kangea, near Godthaab, October 28, 1937. A specimen was taken from the stomach of a white gyrfalcon October 7, 1929, killed near the Post on Southampton Island. Two specimens have been collected on the Arctic Coast of Alaska: one on June 3, 1898, at Point Tangent; and one June 4, 1930, near Point Barrow. A myrtle warbler was collected May 25, 1879, on the northeast coast of Siberia at latitude 67° N. At sea about 100 miles from Cape Hatteras, several myrtle warblers were noted on October 16 and 31, 1930.

_Egg dates._--Maine: 16 records, May 26 to June 23; 10 records, June 11 to 20, indicating the height of the season.

New Brunswick: 10 records, June 5 to 28; 6 records, June 13 to 21.

Nova Scotia: 14 records, May 23 to June 21; 7 records, June 3 to 17 (Harris).

DENDROICA CORONATA HOOVERI McGregor

ALASKA MYRTLE WARBLER

HABITS

The Alaska myrtle warbler is another subspecies that was described many years ago but only recently admitted to the A. O. U. Check-List. Richard C. McGregor (1899) described this warbler, from specimens collected in California, as a western race and named it for his friend Theodore J. Hoover, who collected the type and placed his material at his disposal. He called it _Dendroica coronata hooveri_, Hoover's warbler. In his description of it he says that it is "in colors and markings like _Dendroica coronata_, but with wing and tail much longer." His table of measurements shows that the wings of California males average .15 inch longer than those of eastern birds, and the tails .14 inch longer, less than 1/6 inch! Among the wing measurements of eastern males the individual variation is as great as the difference in his averages, the shortest measuring 2.80 and the longest 2.95 inches! It appears to be a quite finely drawn subspecies.

Dr. Oberholser (1938) says of it: "The Myrtle Warblers breeding in Alaska are recognizable as a western race of this species. They differ from the eastern bird in larger size and more solidly black breast in the male. The upper parts in winter plumage and in the young are also less rufescent than in the eastern bird."

The breeding range of this race, so far as known, extends from northwestern Mackenzie to western Alaska, and southward to central British Columbia and central Alberta. It has been found in winter from California to southeastern Louisiana, in the southeastern United States, and in northern Baja California and in southern Veracruz, in Mexico. It may be commoner than is supposed, as it is recognizable only with specimens in hand.

Dr. Joseph Grinnell (1900) writes of its habits in northern Alaska: