114 U. S. NATIONAL MUSEUM BULLETIN 211 



turned up by the plow. W. J. McLaughlin of Centralia, Kans., 

 writes (Am. Naturalist, vol. 3, p. 493): "During their stay they make 

 themselves very valuable to the farmers by destroying the swarms of 

 young grasshoppers. On the writer's land the grasshoppers had 

 deposited their eggs by the million. As they began to hatch, the 

 yellow-heads found them out, and a flock of about two hundred 

 attended about two acres each day, roving over the entire lot as wild 

 pigeons feed, the rear ones flying to the front as the insects were 

 devoured." 



Economic status. — The foregoing remarks on food throw con- 

 siderable light on the economic status of this bird, for although the 

 yellow-headed blackbird destroys a few useful predaceous beetles and 

 shows a fondness for dragonflies that help destroy other annoying 

 insects, to its credit is the fact that the bulk of its insect food consists 

 of injurious species. It does, however, along with other blackbirds, 

 cause considerable damage to the grain crops, pulling up the seedlings 

 to eat the kernels, feeding on ripening grain, attacking grain in shocks, 

 and injuring corn on the ear while it is in milk. But, as the records 

 show that the various grains were eaten throughout most of the spring 

 and summer, much of this must have been waste grain of no economic 

 importance. On the whole, the bird is probably more beneficial than 

 harmful, except in a few places where it is sufficiently numerous to 

 cause appreciable damage to crops. 



Behavior. — DuBois (MS.) noticed that at certain nests con- 

 taining young, the parents chirped and hovered over their nests when 

 approached, showing much more solicitude than the birds which had 

 only eggs; the latter usually sat off at a little distance and looked on, 

 without any demonstration whatever. Fautin (1941b) found the 

 females very shy about then nests, leaving very silently as the nest 

 was approached, but they never hesitated to drive away another 

 bird from the immediate vicinity of the nest. "The emitting of an 

 alarm call by one of the members of the colony would also cause 

 them to leave their nests and fly to the assistance of the one that had 

 sounded the alarm. Such cooperative behavior was witnessed on 

 several occasions. On one occasion, when an American Bittern 

 (Botaurus lentiginosus) visited the marsh, it was so severely attacked 

 that it could not escape by flight and crawled down among the dead 

 bulrush stems to avoid the onslaught until the confusion subsided 

 and part of the Yellow-heads had retired from the scene of the 

 conflict." 



While I was watching a colony of these blackbirds breeding in a 

 North Dakota slough, a marsh hawk which had a nest not far away 

 happened to fly over the colony; whereupon the blackbirds, yellow- 



