126 U.S. NATIONAL MUSEUM BULLETIN 233 



we remember what a small percentage of bobolink nests are ever 

 found — secreted as they are in grassy meadows and invisible from 

 above because of their semi-domed structure — it may not seem 

 surprising that relatively few records are available. However, it 

 does not follow that the observed incidence of parasitism would be 

 affected by this rather meager sampling. 



Silloway (1917, p. 45, p. 158) found a nest in Judith Basin County, 

 Montana, with 3 eggs of the bobolink and 2 of the cowbird. In this 

 case, the cowbird was the race artemisiae. All the other records known 

 to me involve the eastern race ater. 



In Ohio, Hicks (1934) found the surprising total of 184 nests of the 

 bobolink; of these, 10, or a little over five percent, were parasitized. 

 Roberts (1932, p. 288) lists only one Minnesota record — a nest with 3 

 eggs of the host and 3 of the parasite. 



Eastern Meadowlark 



Sturnella magna (Linnaeus) 



The eastern meadowlark is an uncommon host of the brown-headed 

 cowbird. Bendire (1895, p. 460) noted that "this bird is occasionally 

 imposed upon . . . and an instance has been recorded where a second 

 nest was built over the one containing the parasitic egg." Gross 

 (in Bent, 1958, p. 74) concluded that, in most sections of its range, 

 the meadowlark seems to escape the attentions of the cowbird. He 

 noted that G. B. Saunders, who studied some 50 nests in New York 

 and Oldahoma, never found a cowbird's egg in any of them; neither 

 did Bent with, his varied nest-hunting experience. In southern 

 Quebec, Terrill (1961, p. 8) examined 52 nests, only 1 of which was 

 parasitized. Yet, in Illinois, Gross found four parasitized nests and 

 Eifrig (1915, p. 418; 1919, p. 520) repeatedly found similar instances 

 in the Chicago area "with one or more eggs of the cowbird, and one 

 or more or all the eggs of the rightful owner apparently rolled out. 

 An example of this was found June 24, 1917, with two cowbird eggs 

 inside and four meadowlark eggs outside . . . ." Apparently, the 

 meadowlark is parasitized more frequently in northern Illinois than 

 in many other areas. In Nebraska, Hergenreder (1962) found 31 

 nests, of which 5 had been parasitized. In Wisconsin Lanyon (1957, 

 p. 43) reported that, of 38 nests observed, 6 (16%) contained cowbird 

 eggs. One of these nests was deserted when the parasite made a hole 

 in 1 out of the full clutch of 5 meadowlark eggs. 



The fact that the hosts' eggs so often are found outside the nest is 

 puzzling and deserves study. It is probable that the large egg of the 

 meadowlark is too big for the parasite to carry off, and the egg there- 

 fore may be left on the ground not far from the nest. No mention 

 was made as to whether or not these expelled eggs were damaged; 



