Ridgway.] 318 [February 18, 



ment of modifications toward that form, I have failed to decide by 

 the securing of specimens. I strongly incline to the opinion that 

 the former is really the true state of the case, since in Southern 

 Iowa the two species occur together on the same prairies, and yet 

 each preserves its own characteristics of habits, notes, etc., without 

 mixing or otherwise interfering with the other. (In this connection 

 see T. Martin Trippe, in Proc. Bost. Soc. Nat. Hist., Vol. xiv, 

 pt. ii, Dec, 1872, p. 229.) 



Part III. The times of Migrating and Nesting of the Birds of the 

 Lower Wabash Valley. 



The return of the birds which have passed the winter to the south- 

 ward commences almost with the year, but the species that arrive in 

 January are those which in mild winters are resident, such as Rhino- 

 gryphus aura, Ectopistes migratoria, and various water-fowl. February 

 ushers in but few land-birds, the Seiurus ludovicianus being about 

 the only true non-resident one. In March they begin to arrive in 

 earnest, and from this the number increases until about the 20th 

 of April, after which there is a gradual falling off, but very few spe- 

 cies making their first appearance in May. The height of the 

 " warbler season " is about the 20th of April, when the fruit trees, 

 both cultivated and wild, are in full blossom, during which time the 

 trees literally swarm with the various species of this tribe, engaged 

 in catching the insects which infest the flowers. The summer sojourn- 

 ers do not begin to depart until about the middle of September, but by 

 the end of that month the majority of them are gone. Dendroica do- 

 minica remains until the 13th of September; D. aistiva until the 27th; 

 Seiurus aurocapillus, Vireo favifrons, V. olivaceus and Oporornis formo- 

 sus remain until well along in October; Dendroica palmarum has been 

 shot October 15th; Trochilus colubris was observed Oct. 1st; Chcetura 

 pelagica stays as late as Oct. 20th; Stelgidopteryx serripennis has been 

 observed on the 17th; Galeoscoptes carolinensis on the 15th; Cyano- 

 spiza cyanea about the 15th; Guiraca ccerulea on the 6th; Contopus 

 virens on the 15th; Coccygus erythrophthalmus on the 19th; C. ameri- 

 canus on the 15th. The return southward of species which breed 

 farther north commences before the summer sojourners begin to 

 leave. Empidonax minimus and Seiurus noveboracensis are common 

 in August, but these two species may possibly nest in small numbers. 

 The latter sometimes remains through mild winters. Most of the 

 winter birds come in October, but in one season the snow bird Junco 



