EASTERN CROW 233 



Museum series. One or more eggs dwarfed in size have been found in 

 sets in which the other eggs are normal, but these usually prove to be 

 sterile. 



There are a number of reported cases of erythristic crow eggs, in 

 which there is present an excessive amount of red pigment. In corre- 

 spondence William Rowan, of Edmonton, Alberta, informs me that he 

 has two sets of erythristic eggs that he obtained from central Alberta. 

 They were laid by the same bird in successive years, and he states fur- 

 ther that this same type of Qgg has been found in the same nest for seven 

 successive years. Mr. Rowan believed that these eggs v.'cre unique and 

 represented the first recorded case of erythrism in crow's eggs. How- 

 ever, there are published descriptions of so-called abnormal red-colored 

 eggs that are undoubtedly cases of erythrism. Following are a few that 

 have come to my attention. Bendire (1895) states as follows: In an 

 abnormal set of five eggs, presented by Dr. A. K. Fisher to the United 

 States National Museum collection, four have a pinkish buff ground 

 color, and are minutely speckled with fine dots of ecru drab resembling 

 somewhat in general appearance a heavily marked egg of the American 

 Coot. * * * iri another specimen, presented by Dr. Louis B. Bishop, the 

 ground color is salmon buff and this is blotched with pinkish vinaceous. 

 The entire set of six eggs was similarly colored. Sage, Bishop, and 

 Bliss (1913) mention six pinkish eggs of a set obtained near New 

 Haven, Conn., on May 8, 1884. Jacobs (1935) describes a set of five 

 eggs he found May 1, 1934, in a nest located in a willow tree near 

 Waynesburg, Pa., as follows: 



Throughout the whole set there is not the slightest suggestion of the usual 

 greenish-drab shades. The shell, held to the light, appears a rich cream-white 

 such as seen in the eggs of the Eastern Sparrow Hawk, and on the whole, re- 

 sembles in coloration eggs of the latter collected on the same day. The smallest 

 egg is less thickly marked and contain sparingly scattered hold patches of mauve 

 and maroon purple, which tints are brought out by the brick-red laid over varying 

 shades of lilac and lavender, the majority of them all on the smaller half of the 

 shell. It is a beautifully spotted egg with brick-red, mauve and maroon purple 

 about equally apportioned and equalling the amount of lilac and lavender shades 

 which are untouched by the reddish pigment. 



The ground color of the four eggs originally rich creamy-white with lavender 

 blendings in paler underlays is heavily mottled over with brick-red giving the 

 shells a uniform rich vinaceous appearance, over which are diffused blotches of 

 strong vinaceous-cinnamon blending into the underlays. Thus we have, in these 

 five crovi/ eggs, specimens appearing like huge Cactus Wren eggs but the general 

 red shade is really stronger than that of the wren's eggs. 



Incubation. — The incubation period of the crow is 18 days. One brood 

 is reared each year, but in the southern part of the nesting range two 

 broods each season are not unusual. Both male and female may take 



