244 Correspo?/dcnce. [Apri: 



Work of the Delaware Valley Ornithological Club During 1890. 



To THE Editors of the Auk : — 



Dear Sirs: In the ]n\\ luiiiiber of 'The Auk' was published an ac- 

 count of tlie formati(;n and the objects of the Delaware Valley Ornitho- 

 logical Club, and as we have now completed a year's studj of the birds in 

 the vicinity of Philadelphia it luay be of interest to give a brief sLinimary 

 of the results of our work. 



We have had six observers regularly in the field during the migrations 

 besides having luore or less frequent reports from four others. Our sta- 

 tions of observation being clustered around Philadelphia, the extreme 

 points not more than twelve miles apart, we found a study of the north- 

 ward progress of the luigrating birds, from point to point, out of the 

 question, as the large waves affected all our stations in a single night, and 

 in tlie case of stragglers the first records came from the stations farthest 

 up the river quite as frequently as from those lower down. 



In some cases it would seem as if the advance guard of a wave had 

 halted just beyond our lower stations one night and had not reached the 

 others till the next night. 



The records also seem to indicate that the migrating host spreads out 

 farther on the New Jersey side of the river than on tbe Pennsylvania ^ide, 

 or perhaps the birds sheer otF to the east where the river bends north- 

 ward at Philadelphia; at any rate the arrivals at Haddonfield, N. J., seem 

 to average earlier than at points to the northwest of Philadelphia. Whether 

 future investigations will bear out this theory remains to be seen. 



Recognizing the fact that the common species furnish much the best 

 basis for the study of migration, we iiave endeavored to get as full data 

 concerning them as possible, taking the exact numbers seen day after 

 day, each observer covering nearly the same section of country daily and 

 using the glass much more than the gun in his identifications. The 

 result was that we found the numbers of many species continuing to fluctu- 

 ate with the waves of migration for some time after the species became 

 common: thus showing that tlie date of the first arrival, 'bulk ariival,' 

 and last date by no means completely describe the migration of a species. 



During the year, 204 species have come imder our observation. Of 

 these 86 were recorded through June and July and were proved either by 

 the experience of tiiis year or of former years to be breeders within our 

 district. According to Dr. Allen's lists (Bull. Mus. Comp. Zool., II, 

 p. 3S7) twelve of these are ciiaracteristic of the Carolinian fauna, and four 

 of the Alleghanian, while seventy are coinmon to both, many being 

 widely distributed during the breeding season. 



During January and February fifty-five species came under our obser- 

 vation. 



Some of the more interesting records of the year follow : 



Uria lomvia. — One shot on the Delaware at Chester, Dec. 29. 



Oceanodroma leucorhoa. — One shot at the mouth of Darby Creek, on 

 the Schuylkill River, by Mr. Wm. V. Wiltbank, Dec. 18. 



