Vol. XXXVII] 



1920 



] Kennard, Breeding Habits of Rusty Btackbird. 41" 



between five and ten millimetres, and so pressed onto its surround- 

 ing frame as to become, when it hardens, a part of it. 



After the bowl has been carefully modeled and smoothed off on 

 the inside, it is lined with the fine, long green leaves of grasses that 

 grow in the swamps thereabouts, and is finally topped off with 

 dried grasses and fibres of various sorts, and a few thin, bendable 

 twigs. In recently constructed nests I have found the green lin- 

 ing to be absolutely constant, although as incubation progresses, 

 these grasses, of course, gradually turn brown. The diameter 

 of the nest when finished, just across the outside of the bowl, 

 averages about twelve centimetres, while the diameter of the en- 

 tire structure, except for a few outreaching twigs, varies from four- 

 teen to twenty centimetres. The usual measurements from foun- 

 dation to top of bowl are from eight and one-half to nine centi- 

 metres. 



Audubon in Vol. II of his 'Ornithological Biography,' writes 

 that " The nest is not so large as that of the Redwing, but is com- 

 posed of much the same materials. In Labrador I found it lined 

 with moss instead of coarse grass. The eggs are four or five, of a 

 light blue color, streaked or dashed with straggling lines of brown 

 or deep black, much smaller than those of the Redwing, but in 

 other respects bearing considerable resemblance to them." 



Such nests as Audubon may have found, must, if they were 

 Rusty Blackbirds', have been very exceptional, and the above in- 

 formation is certainly misleading. The female Rusty is consid- 

 erably larger than the female Redwing, and builds a much larger 

 and bulkier nest, and the eggs, four or five in number, are ovate 

 in shape, larger, more fully rounded and less elongated than Red- 

 wing's, which they in no way resemble; and smaller than those of 

 the Bronzed Grackle; the fifty-three in my collection averaging 

 25.57 millimetres x 18.56 millimetres. 



Bendire describes them well as follows: "The ground color 

 is a light bluish green, which fades somewhat with age, and is 

 blotched and spotted more or less profusely, and generally about 

 the larger end of the egg, with different shades of chocolate and 

 chestnut brown and lighter shades of ecru, drab, and pearl-gray. 

 The peculiar scrawls so often met with among the eggs of our 

 Blackbirds are rarely seen on these eggs, which are readily dis- 



