Attentiveness of Cranes at Their Nests

Abstract

LITTLE has been published on the attentiveness of cranes at their nests. R. P. Allen (The, Whooping Crane, New York, Natl. Audubon Soc., Research Rept. no. 3, 1952; see pp. 184-190) presented some notes on the captive Whooping Cranes (Grus americana) which nested in 1949 at the Aransas National Wildlife Refuge, Texas. I related some notes on the Sandhill Crane (G. canadensis) in Michigan and Georgia (The Sandhill Cranes, Bloomfield Hills, Michigan, Cranbrook Inst. Sci., Bull. 29, 1949, see pp. 86-90 and 97-99; Auk, 67: 38-51, 1950); on the Sarus Crane (G. antigone) in the Lincoln Park Zoo, Chicago (Auk, 64: 602-615, 1947); and on the White-naped Crane (G. vipio) at the Detroit Zoological Park, Detroit, Michigan (Auk, 68: 194-202, 1951). Cranes are very attentive to their eggs. If they do leave the nest, they usually remain nearby where they can easily watch the nest. On three occasions, however, I have found Sandhill Cranes away from their nests during midday when there was a warm sun. Also, early one morning my wife and I found the nest of a Crowned Crane (Balearica pavonina) in Northern Rhodesia with the eggs unattended. We did not see either bird in the hour we were in the vicinity. Later in the day we returned to the nest to see if it was deserted, and found that it was not. Nevertheless, most cranes seldom if ever leave the eggs unattended. This paper summarizes my observations of the attentiveness of various species of cranes. Many of the notes on the Sandhill Crane were made at the Phyllis Haehnle Memorial Sanctuary, Jackson County, Michigan. Here I was able to watch the largest southern Michigan population from a point on a nearby hill, and activities at all or nearly all nests could be observed, except on rainy days or days with poor visibility, when this was not always possible. More was learned here, however, than I have been able to learn elsewhere. Usually I remained in my automobile so that I would not frighten the cranes. On many occasions I also spent the night there. By similar methods, I watched cranes in Africa. At one place I was able to watch nests of both Crowned and Wattled (Bugeranus carunculatus) cranes which were nesting only about 500 feet apart. At other places I observed nests of the Stanley Crane (Anthropoides paradisea). In Sweden, in May and June, 1963, I was also able to watch European Cranes (Grus grus) at their nests, in one place from a specially built tower, in another from a nearby woodland. In May, 1950, I spent eight days watching a pair of Whooping Cranes at their nest at the Aransas Refuge in Texas. Here the sexes of the two captive birds were known. In the wild I presumed that the larger bird at a nest was the male. Usually the pre-