198 APPENDIX 



breeds regularly to southern Minnesota and northwestern 

 Nebraska- and rarely in Kansas. The breeding range then 

 dips strongly to the south in the mountains through Colo- 

 rado to northern New Mexico (La Jara and Stinking 

 Spring Lakes), central Arizona (Stoneman Lake, alti- 

 tude 6,200 feet), southern California (Los Angeles 

 County) northern Lower California to about latitude 31° 

 and probably northwestern Chihuahua (Pacheco.) The 

 breeding range on the Pacific slope extends north at 

 least to central British Columbia (Cariboo District) ; in 

 the interipr to Great Slave Lake and Hudson Bay (York 

 Factory.) The above' is the normal breeding range, but 

 this species has the peculiar habit of establishing colonies 

 far to the soiithward. Such colonies have been discov- 

 ered at Santiago, near the southern end of Lower Cali- 

 fornia, in the Valley of Mexico, at the Lake of Duenas, 

 Guaterhala, and on the islands of Cuba, Porto Rico and 

 Carriacou. The breeding season' of these isolated colo- 

 nies bears no relation to the usual breeding time in the 

 •bird's ordinary range. In northern North Dakota the 

 earliest eggs are deposited the first week in June ; Mani- 

 toba and Saskatchewan incomplete sets were found the 

 middle of June; the same date — the middle of June — 

 marks the deposition of the eggs in central Colorado. 

 The first half of June may be said to be the usual time for 

 the beginning of nesting. Oh Cape Cod, Massachusetts, 

 dOwny young were taken Aug. 17; in northern NeW Mex- 

 ico, Sept. 17; in southern Lower California, Nov. 16; at 

 Lake Duenas, Guatemala, in June; while in Cuba and 

 Porto Rico eggs were taken in November, and on Car- 

 riacou Island in January. 



THE END. 



