1921
naturally be the most likely one to know the exact requirements her particular nest demanded. The subject, however, is not an easy one to handle by any means, for in many cases the male is an active worker, and may know equally well those particular requirements. Now most of us I imagine have watched a pair of Bluebirds (Sidia sialis sialis) at nesting time, inspecting all the likely looking holes in a number of orchard or other trees. First one bird goes in and inspects a hole, then the other proceeds to do the same thing, and on coming out it often appears as though a weighing up of the pros and cons were taking place, but unless one is able to follow them about until the final hole is decided upon, it seems almost impossible to form any adequate idea which sex eventually decides the matter. However. I was fortunate enough on two occasions to be able to follow a pair of Chickadees (Penthestes atricapillus atricapillus) about, until the final hole was selected. In both instances this was decided upon very rapidly, first one bird inspected the hole, and then the other (as they had done previously in the case of several others), after which they both retired to a nearby tree, where some form of understanding not apparent to our senses, was evidently arrived at, for with scarcely a moment's delay, first one bird, and then the other, again entered the hole, and commenced to remove the dead and decaying chips, and in due course the nest in each case was constructed. In these two instances it would appear as though the final selection was entirely a mutual one, which might have been expected, seeing that both sexes take part in the construction of the nest, the same as the Bluebirds. Now in the case of a large majority of the warblers this is not so, or at least, it has not been apparent in those which have come under my observation, for the males rarely seem to take any very active part or interest, either in the construction or exact location of the nest. This was particularly apparent in the case of the Blackburnian Warbler (Dendroica fusca) mentioned in my "Singing Tree" paper,[1] for I am disposed to think, (in view of the very faint indications there were of a nest) that the date June 10, 1918, was the very one on which the exact spot for the nest was finally decided upon. If this was so. I am in a position to state
- ↑ 'Auk,' Vol. XXXVI, 1919, p. 346.
