LIFE HISTORIES OF NORTH AMERICAN WILD FOWL 161 



(Washington County), eastern Massachusetts (Cape Cod), southern 

 Rhode Island (Seaconnet Point), and central New York (Seneca 

 River), Extreme southern breeding colonies have been found in 

 southern Lower California (Santiago), the Valley of Mexico, at the 

 Lake of Duenas, Guatemala, and in the West Indies (Cuba, Porto 

 Rico, the Grenadines, Carriacou, etc.), many of which are probably 

 permanent colonies. 



Winter range.— The, northern portions of the breeding range are 

 vacated in winter. It winters abundantly on the Atlantic coast as 

 far north as Chesapeake Bay and more rarely north to Long Island 

 and Massachusetts; south to Florida, the Bahamas, and the West 

 Indies (Cuba, Porto Rico, Jamaica, Martinique, Grenada, Barbados, 

 etc.). On the Pacific coast, from southern British. Columbia (Bound- 

 ary Bay) southward to Lower California, Guatemala, and Costa 

 Rica (Irazu). In the interior north to central Arizona (Pecks 

 Lake), southern Illinois, and western Pennsylvania (Erie). 



Spring migration. — Early dates of arrival: Massachusetts, March 

 20; Utah, Bear River, March 30; Minnesota, Heron Lake, April 3; 

 Ohio, Oberlin, April 7; Manitoba, southern, April 2G; Alberta, 

 Edmonton, May 1. Average dates of arrival: Pennsylvania, Erie, 

 April 16; Ohio, Oberlin, April 15; Nebraska, April 7; Minnesota, 

 Heron Lake, April 10 ; Wyoming, Cheyenne, April 21 ; Manitoba, 

 southern. May 5. 



Late dates of departure: Kentucky, Bowling Green, April 18; 

 Lower California, Colnet, April 8. 



Fall migration. — Early dates of arrival : Virginia, Potomac 

 River, August 20 (average September 30) ; Massachusetts, Pem- 

 broke, September 5 ; West Indies, Barbados, September 13. 



Casual records. — Accidental in Bermuda (November 24, 184G) and 

 Alaska (Kuj^reanof Island, August 15, 191(5). Rare straggler in 

 Nova Scotia and New Brunswick. 



Egg dates. — California : Thirty records, April 26 to August 11 ; 

 fifteen records. May 22 to June 10. North Dakota : Twelve records, 

 June 8 to July 19; six records, June 13 to July 9. Colorado: Nine 

 records, May 31 to August 6. Porto Rico : December to March. 



NOMONYX DOMINICUS (Linnaeus) 

 MASKED DUCK 



HABITS 



This curious little duck resembles the ruddy duck in many ways 

 and has been placed by some writers in the same genus with it. It 

 is a tropical species, with its center of abundance somewhere in 

 eastern South America, found frequently if not regularly in some 



