BULLETIN No. 37 96 



disturbed. Tlie nest is often built in three days. The 

 period of incubation in one instance was thirteen days, 

 and the young left the nest on the morning of the tenth 

 day. From fifteen to seventeen pairs noted, 32 



48. Blue=wing:ed Warbler Helmintliophila pinus. A 

 common inhabitant of the rather open swampy 

 thickets, upland clearings, neglected pastures and 

 fence rows, building its nest midst the tangle of 

 young saplings, wild grape vines, blackberry and 

 raspberry bushes, in a clump of grass, goldenrod 

 or brier shoots. Wiien the female is sitting close, the 

 male makes little excursions in all directions, singing 

 his locust song. From ten to thirteen pairs were ob- 

 served. 22 



49. Yellow Warbler Dendroica cestiva. While said to 

 be abundant in some parts of the county, it is here 

 comparatively rare, hi the early summer of 1899, I 

 observed a male taking a bath in a spring, and have 

 since found a pair frequenting an upland clearing but 

 they could not be traced to their nest at any time. 1 

 think that this section would scarcely yield a single 

 pair to the square mile. 2 



50. Oxenh'ird Seiurus anrocapilliis. From early May un- 

 til July the loud asserting chant of this Warbler may be 

 heard everywhere until the very woods resounds. It 

 would be folly to atteinpt anything more than an ap- 

 proximate figure of the number of individuals with 

 less than practically unlimited time and energy. My 

 estimates were obtained by repeatedly visiting every 

 tract of woods at different times of the day, and taking 

 the average as the probable number of breeding birds. 

 The total of forty-one pairs 1 regard as conservative. 82 



51. Kentucky Warbler Geotblypis formosa. It would 

 seem almost incredible that so keen an ornithologist as 

 Alexander Wilson should have overlooked this bird in 

 Pennsylvania if it had not been uncommon or local at 

 that time. Discovering it in Kentucky and subse- 



