224 THE NATURALIST OF THE ST. CROIX 



have to confess to entire ignorance in regard to the time 

 of incubation of all the species." Dr. Wood quotes Mr. 

 Gentry in his work on the Birds of Eastern Pennsylvania 

 as making all the birds in the family occupy a different 

 period, spending only one or two nights in building a 

 nest, and writes: "I watched one this season which 

 took five days. Perhaps Connecticut birds are not as 

 smart as Pennsylvania birds. Gentry is very particular 

 to have each of the six owls occupy a different period of 

 incubation, from fifteen to twenty-four days." In answer 

 to a request for Mr. Boardman's views he writes : 



In answer to your question about the time, or period of incuba- 

 tion of our hawks and owls, I must say that I know but little 

 about it, but most every set of eggs I take I find them in different 

 stages. The truth is, we have so many crows, black birds, jays, 

 cuckoos, etc., etc., that as soon as the birds begin to lay one bird 

 has to remain on the nest for protection of the eggs and the first 

 laid eggs are much more advanced than the last. I find this in the 

 eggs of small birds as well as of the large. I took last night a 

 nest of Red-bellied Nuthatch made in a hole so small that nothing 

 larger than a mouse could get in. Out of six eggs three were 

 nearly fresh ; of the others one was quite hard set. I have found 

 in a grebe's nest, fresh eggs and young birds. So to get at the 

 period of incubation we should have to count from the first eggs 

 in case of most of our birds. That may be the reason Mr. Gentry 

 has so much difference. 



Another matter about which these naturalists had con- 

 siderable correspondence was whether the Black and 

 Rough-legged Hawk were one and the same species. As 

 early in their correspondence as 1868, Dr. Wood had 

 asked Mr. Boardman's views upon this subject and in a 

 letter dated October 12 of that year he writes : 



About the Black and the Rough-legged Hawk being the same 

 bird, I would say I have some doubts aud some of the reasons are 



