\,.l \ \ \ 



l'.U.i 



Jewel, North American Birds in Panama. 423 



canoe and will soon he lost under the rising waters of (Jut nil lake. 

 Tims passes perhaps, tin- foremost land-mark of Middle American 

 ornithology. 



In presenting the dates for the species given below, attention 

 might he called to the very short time which some northern birds 



are absent from the tropics. 



The Spoiled Sandpiper {Acbitis maeularia) for example, is re- 

 corded in every month of the year, except May and June, and this 

 by intermittent observance covering hut little more than one year's 

 time. It is, of course, probable that some few individuals of this 

 species may fail to join the northward movement, and for some 

 reason or other, spend the entire breeding season in the tropics; 

 hut the arrival of apparently healthy birds in early August, indi- 

 cates how quickly the return trip is made after the family is reared. 



The Semi-palmated Plover (dEgialitis semipalmata) is still earlier 

 in making the return trip, some arriving on the Isthmus shortly 

 after the middle of July. 



Along with the group of early Shore Birds and Swallows, is 

 another Passerine bird which arrives in Panama while it is yet sum- 

 mer in the temperate zone. This is the Yellow Warbler (Den- 

 droiea oestiva aestiva) which certainly may be found in Panama 

 in every month hut June and July. This means that long before 

 the last birds have left the breeding grounds in the northern United 

 States, the advance guard is in Panama. Again, in the spring, when 

 firsl arrivals are choosing nesting sites as far north as New England 

 many of their kind are still flitting and feeding among the mangoes 

 and guavas three thousand miles southward. Certainly a remark- 

 able distribution. 



All birds of the A. (). U. Check-List which were identified with 

 certainty, are included in the following list. For several identifi- 

 cations of subspecies, I am indebted to Mr. W. W. Grant of Engle- 

 wood, V J., and Mr. \Y. de Witt Miller of the American Museum 

 of Natural History. 



1 . Larus atricilla. Laughing Gull. — A single individual was seen 

 at the mouth of the old French canal near Col6n on December 10 and 

 three more at the same place on December 13, 1911. 



2. Sterna hirundo. Common Tern. — One bird of this species was 

 shot from a flock of the following at Gatun, on December 3, 1911. A 

 single bird was taken on Gatun lake on June 9, 1912. 



