Conflict Between Two Desires

Montana and Cherree had completed their nest. Three eggs had been laid and one nestling hatched. It was almost time for the youngster to leave the nest, when the urge came to Cherree to rear another brood. She examined the old nest; decided, apparently, that a little building up of the edge would make it as good as new. That the baby was not quite ready to leave did not seem to bother the mother bird. Tana was doing most of the feeding, anyway, so Cherree had time on her hands-or should we say on her wings?-and seemed to possess an overpowering urge to hurry before it was too late for a second brood. She began collecting rootlets, which she carefully placed on the inner edge of the nest, then molded them with her breast. With the growing youngster in the way, this was a difficult feat.

Progress was slow and much of the material fell to the ground. As it has not been known hitherto that evening grosbeaks had two broods in a season, I was anxious that nothing should interfere with what might be an important discovery. So an abandoned robin's nest was fastened close to the grosbeak's nest, relined with grass and the youngster placed in it. There was no objection from either parent, and refinishing the old nest went on with more speed. Cherree, however, did not neglect her baby. To feed it and to build had an equal appeal, leading to conflict between two desires. Once, as she flew to the nest with a pliable twig, the nestling called loudly for food. Cherree hopped to its side and it gaped, ready for food. The mother wanted to feed her offspring, yet wanted to use that twig in her nest. Finally, as the nestling continued to gape, she placed the twig crosswise in the wide-open mouth, which was no solution at all.

Comparatively little is known of the nesting habits and behavior of evening grosbeaks in the wild. Probably not more than fifty or so nests have been found. Breeding in captivity has been attempted for many years in various countries, without success until 1938, when a Winnipeg naturalist succeeded in rearing part of a brood. To gain knowledge of how evening grosbeaks construct their nests; what material they prefer; the incubation period, of which practically nothing is known; and other facts, I tried for several years to induce these birds to breed. In 1936 I succeeded in having them build, lay eggs, and hatch young, but the nestlings lived only a few days. Failures followed during subsequent seasons, until 1942.