Part 59

"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:

Hoover's Warblers were numerous summer residents of the timber tracts throughout the Kowak Valley from the delta eastward. In the latter part of August scattering companies were frequenting the spruce, birch and cottonwoods, among the foliage of which they were constantly searching, with oft-repeated 'chits,' just as are their habits in winter in California. The last observed, a straggling flock of six or eight, were seen in a patch of tall willows about sunset of August 30th. The following spring the arrival of Hoover's Warblers was on May 22nd. They were already in pairs and the males were in full song. At this season they were confined exclusively to the heavier spruce woods. In the Kowak delta, on the 23rd of June, a set of five considerably-incubated eggs was secured. The nest was in a small spruce in a tract of larger growth, and only four feet above the ground. It is a rather loose structure of fine dry grass-blades, lined with ptarmigan feathers.