APPENDIX 173 



from the northwest. Occasionally birds are found in win- 

 ter as far north as Rhode Island. The species is common 

 during the winter in the Carolinas, less common in Flori- 

 da -and Cuba and rare in the Bermudas, the Bahamas, 

 Jamaica, Porto Rico, St. Thomas and Trinidad. It is re- 

 corded from Costa Rica and is a rather common winter 

 resident of northern Guatemala and much of Mexico 

 north of the Valley of Mexico. The winter home in the 

 Mississippi Valley extends north to Illinois and in the 

 west to New Mexico, Arizona, Utah (probably) and to 

 southern British Columbia. It is probably most common 

 during the winter along the Pacific coast. 



Spring Migration. This begins late in February, and 

 by early March the species is north of its winter home. 

 Average dates of arrival are : Western New York, March 

 23; Erie, Pa., March 24; Oberlin, O., March 17; southern 

 Michigan, March 25; Keokuk, la., March 15; central Ne- 

 braska, March 17; Loveland, Colo., March 10. The fur- 

 ther advance of the species is somewhat slow. The ave- 

 rage time of reaching Heron Lake, Minn., is March 29; 

 southern Manitoba, April 20 ; Terry, Mont., April 8. The 

 first individual was seen at Indian Head, Saskatchewan, 

 April 24, 1904, and at Osier, Saskatchewan, May 2, 1893. 

 These dates indicate an average speed of seventeen miles 

 per day from central Nebraska to Heron Lake and 

 eighteen miles per day thence to southern Manitoba. 

 The average rate from Colorado to Montana is sixteen 

 miles per day, and the same rate continued northward 

 would bring the first baldpate to Indian Head and Osier 

 at almost exactly the stated dates. If the birds of the 

 Mississippi Valley pass northwest to the Mackenzie Val- 

 ley, this rate of migration would bring them to Great 



