256 



GENERAL HABITS 



known to crash through plate glass windows a quarter-inch thick. Forbush'" states that they 

 have even flown into locomotive headlights. 



The impulse underlying this behavior is not clearly understood. Several theories have been 

 advanced, at different times, to explain it. An anonymous writer in the Rural New Yorker, in 

 1875, attributed to an "old hunter" the opinion that the birds were frightened by the falling 

 leaves. A writer in Forest and Stream, in 1878'"'^ states it is a provision of nature against 

 detrimental inbreeding. Forbush"" suggests the possibility of an inherited instinct of migra- 

 tion occurring sporadically among the birds. The same author credits Seton with the obser- 

 vation that "'it is a trait of the young birds, which they exhibit during the first season and 

 sometimes in the second, but never afterward". On the other hand. Gross'"" and Allen", find- 

 ing infestations of the stomach worm (Dispharynx) in grouse picked up dead under similar 

 circumstances, suggested the possibility of disease as the cause. 



While definite experimental data are lacking, it seems probable that this phenomenon is 

 largely a characteristic of young birds seeking a territory in which to "paddle their own 

 canoe". Of 15 specimens with this history which have been examined during this Investi- 

 gation*, all were birds of the year. The time of usual occurrence in the fall coincides with the 

 period immediately following the breaking up of most of the broods. Apparently, it repre- 

 sents Nature's way of dispersing the surplus among the current season's crop. 



During this period, some stimulus, we do not know what, spurs the young birds to leave 

 the family group in which they have traveled all summer and to strike out for themselves. At 

 this time they become noticeably wilder. In corroboration of this, it is significant that, each 

 fall, in late September or early October, the hand-reared birds in wire pens at the Research 

 Center almost overnight became markedly more nervous and jumpy. This condition often 

 lasts until Thanksgiving time. While such environmental changes as the falling of the leaves 

 may have some minor influence, it seems certain that the controlling factor is inherent in 

 the bird itself. 



Although the records are too scattered to be indicative, the incidence of "crazy flight" 

 probably tends to vary directly with the fall abundance of grouse. Furthermore, it has been 

 demonstrated that populations in excess of the saturation point decrease through dispersion 

 at this season. 



Of problematical significance is the record of a bird marked by tying a bell to its wing, 

 which was found dead sometime later, having broken its neck flying into a tree. This sug- 

 gests the possibility that irritation resulting from injury or perhaps disease, may sometimes 

 produce, in individual birds, reactions superficially resembling crazy flight. 



Spring Shuffle 



As noted above, the territory in which they pass their first breeding season becomes the 

 permanent home of most grouse. The majority make this choice during the preceding fall. 

 Some, however, either are laggards or become dissatisfied with the covert in which they 

 spent the winter. The result is a "spring shuffle" in which such individuals wander about until 

 they become settled. This niovcmenl. which takes place in late March and early April, is on 

 a much smaller scale than thai of the fall and the birds seldom exhibit the wild recklessness of 

 the crazy flight season. 



During the spring, birds are often picked up dead after having flown into some obstacle. 

 Such instances have been thought, by many, to represent a recurrence of the crazy flight im- 



* Since the burta of Fabricut bai been employed a* an indel of age. 



