Ten Spring Bird Lists 191 



Examples are the liaAvks, Henslow's sparrow, the butcher- 

 bird and the white-breasted nntliatch. However, the local- 

 izing of birds has its advautages when the observers have 

 become well acquainted with the couutiy. They are able 

 to call upon certain birds, as it were, and the regularity 

 with which representatives of the species are found in a 

 given area, year after year, is remarkable. 



In the earlier years, it was In' no means the easiest 

 thing in the world, to get a robin or crow blackbird on the 

 list of birds seen. But since that time these species have 

 become decidedly more common ; other breeding birds 

 which have shared this tendency to a greater or less de- 

 gree, are: the orcliard oriole, migrant shrike, and mocking- 

 bird. Among strict migrants the Caj^e May and Tennessee 

 warblers have been seen more frequently in recent seasons 

 than they were ten to fifteen years ago. The European 

 starling has been steadily increasing in numbers since its 

 first appearance in our region in 191o. Decrease in num- 

 bers within the period of the lists here presented, can 

 hardly be ascribed to any species except the English spar- 

 row; although in a period of about twice as long, hawks 

 and owls in general are known to have become much 

 scarcer. 



Consideration of the bird lists here presented brings 

 up the question among others as to what evidence they 

 give as to the height of migration in the District of Co- 

 lumbia region. The ten annual excursions here cited rep- 

 resent every date from May 9 to 18 except tlie 16th. The 

 days on which more than the average number of sjiecies 

 were seen were 11, 11, 13, 14 and 17. The longest two lists 

 were obtained on 11 and 13. These data confirm the usual 

 impression among bird students here that the height of 

 migration is apt to occur from May 10 to 15. 



The peak of migTation then occurs at a period when 

 some of the later migrants normally are just beginning to 

 arrive, as the least bittern, yellow-bellied and alder fly- 

 catchers, Connecticut and mourning warblers and the gray- 

 cheeked thrush. In the average season, therefore, most of 

 these species are not likely to be seen on a trip taken dur- 

 ing tlie actual height of migration. If the date is post- 



