290 GENERAL HABITS 



Of 2,016 nests examined from 1930 to I9-i2, 11 contained pheasant eggs in addition to 

 those of the grouse. There seems to be little question, however, that such instances are the 

 result of a parasitic tendency on the part of the pheasants involved rather than competition 

 for the nesting site. 



Another report'^'' tells of nests of a grouse and a domestic hen that were but four feet apart. 

 This account also goes on to relate that the grouse nest was broken up, following which the 

 grouse laid several eggs in the hen's nest. 



Analysis of the relative proximity of different nesting grouse has revealed some wide varia- 

 tions. The examination of a large number of nests over the last 12 years has sliuwn that 

 female grouse seldom nest within 100 feet of each other and that intervening distances of over 

 .500 feet are the rule. Nevertheless, scattered instances of two or more nests quite close 

 together have been recorded. In one, three nests were found all within 50 to 100 feet of each 

 other. In another, two nests were 50 feet apart, and in a third instance the distance was 75 

 feet. Furthermore, a number of grouse nests have been found in which there was every indi- 

 cation that two hens contributed to the clutch present. 



It seems probable that nesting grouse exhibit little, if any, intolerance toward each other. 

 The usual scattered distribution of nests is more likely the result of a lack of need for any 

 greater concentration. In those cases where grouse nests have been found close together, it is 

 possible that both females mated with the same cock. 



Desertion 



Occasionally, female grouse desert their nests. Such action is usually the result of undue 

 interference with the bird by some outside agency. Rarely is it due to a cessation of the 

 maternal instinct. Desertion from the former cause probably occurs most frequently before 

 any eggs have been laid. On both the Connecticut Hill and Adirondack study areas, perfectly 

 formed nests have been found in which eggs were never laid, though, in some cases, the female 

 was flushed from the spot. Later, a nest was often found a short distance away iti w'hich a full 

 complement of eggs was deposited. In one case, the second nest was directly beside the first. 

 If the provocation is strong enough, however, desertion may occur at any time, although the 

 lirobability decreases markedly as incubation progresses. 



It is probable that desertion, due to a cessation of the maternal instinct, occurs largely in 

 connection with late rcnesting birds. One bird incubated until July 5 before giving up. In 

 this case, however, examination of the eggs showed them all to have been infertile. 



It is, of course, evident that the death of the female away from tlic nest would give the 

 impression of desertion. Thus, in analyzing such records, any error will tend to increase the 

 percentage of frequency. In any case, however, the incidence of desertion*, after eggs had 

 been laid, has been almost negligible among the nests examined during this Investigation. 



That the birds will endure a considerable amount of interference, especially during the latter 

 part of the incubation period, without deserting, is evidenced by the experience of the authors 

 in trapping nesting birds for marking purposes. Such trapping operations were carried on at 

 the nest site during the last few days prior to hatching. Of 128 females so handled on the Con- 

 necticut Hill area, only eight or 6.2 per cent deserted. 



In this connection, one bird, which accidentally broke its wing in a trap, nevertheless re- 

 turned to its nest, hatched the eggs and successfully reared the resultant brood. Although crip- 



• See Chaplet \\\. p. S27. 



