338 MICHIGAN BIRD LIFE. 



it is not possible to generalize safely in regard to either species. They 

 seem to arrive from the south at about the same time, which is early in May 

 in the southern part of the state and from five to ten days later in the 

 Upper Peninsula. Average dates for Detroit and Lansing will range from 

 May 10th to 20th. 



This is one of the birds whose voice is often heard at night and its usual 

 call, coo-coo-coo, or kuk-kuk-kuk, is common to both species and is familiar 

 to most outdoor people. Both the cuckoos have numerous variations 

 of this call, and several entirely distinct notes, but our best observers are 

 unwilling to assign any one of these notes exclusively to either species, 

 and we know of no characteristic note belonging to the Yellow-billed Cuckoo. 



Nest building begins ordinarily in June, but not commonly until the 

 middle of the month or even later. According to Bendire " In the northern 

 part of its range the breeding season is at its height during the latter part 

 of June and the first week of July, and here one brood only is reared, while 

 in the south they sometimes raise two." The nest is a very simple affair, 

 consisting of a little platform of twigs, leaf-stems, and perhaps a few catkins, 

 slightly hollowed to receive the eggs, and lodged rather than placed in the 

 crotch of a bush, among a tangle of vines, or sometimes on the horizontal 

 spreading branch of an evergreen. Not infrequently the old nest of some 

 other bird is used with only slight repairs or additions. The eggs are three to 

 five, pale blue, often more or less nest-stained, and always unspotted, though 

 frequently clouded or "water-marked" in a manner which is easily recog- 

 nized but not readily described. They average 1.21 by .88 inches. 



It seems to be a fact that the two species of cuckoos not infrequently 

 lay their eggs in each others nests, and this by many is considered a relic 

 of the parasitic habit so strongly developed in the olcl world cuckoos, which 

 usually build no nests of their own, but impose the care of their eggs and 

 young on other and mostly smaller birds. Single cuckoos eggs are not 

 infrequently found in the nests of other birds here in Michigan, but not 

 more often perhaps than we find eggs of the Robin, blackbirds and some 

 sparrows. In this connection it should be noted that comparatively fresh 

 eggs and newly hatched young are sometimes found in the same nest, 

 although as a general rule the set is completed before incubation begins. 

 It is difficult to believe that only one brood is reared in Michigan each season, 

 since eggs are common in June and all through July and August, even a few 

 sets being found in September. It is possible that these are merely second 

 layings by birds which have been unfortunate with their first nests, but it 

 seems much more likely that many individuals rear two broods 



The food of this cuckoo consists very largely of insects, and probably 

 we have no bird which is more valuable to the orchardist and fruit grower. 

 The careful studies made by the Department of Agriculture at Washington 

 have shown that more than 75 percent of the food consists of insects, and 

 these are almost all of injurious kinds. It is particularly fond of cater- 

 pillars and appears to delight in those forms which are covered with hairs 

 and spines. It is a common thing to see a cuckoo perch near a nest of tent 

 caterpillars (Clisiocampa) , and quietly swallow one caterpillar after another 

 until seven or eight have been taken, then rest for half a minute or more 

 before eating an equal number, repeating this action several times until 

 the appetite is satisfied or the supply of caterpillars exhausted. In several 

 instances more than one hundred tent caterpillars have been taken from 

 a single cuckoo's stomach, and the bird is almost equally destructive to 

 various other hairy caterpillars. Even those caterpillars which are covered 



