I2ii COVER CHARACTERISTICS AMJ SHELTER REQUIREMENTS 



While some nests have been found in each type, nieadowlands (type A) supporting occa- 

 sional trees or shrubs, and coniferous cover (type Hj are least utilized for this purpose. 



Woodland types are strongly favored as nesting cover, 899 out of 1,270 nests being found 

 therein. 



Of all the woodland types, nests are most likely to be found in second-growth woodlands 

 (types E and EH), for 565 (48.4 per cent) were located there. They are least likely to be 

 placed among conifers in which but 52 (4.4 per cent) were discovered. 



Only about one-third as many birds are likely to place their nest in mature woodlands as in 

 second-growth cover. 



Except for mature woodlands, which are apt to be fairly clear of nmch undergrowth or 

 ground cover, all of the most likely cover types chosen are characterized by providing con- 

 siderable summer food for broods. This is especially noticeable with respect to spot-lumbered 

 areas (type G), which, although small in extent b> comparison with other types, attracted 

 105 birds (9.0 per cent). 



There is a tendency for the nests to be located in types deficient in conifers. Thus three 

 times as many birds nested in overgrown fields deficient in evergreens (type C) as located 

 their nests in overgrown fields where a substantial number of conifers (type D) were present. 

 A somewhat lower ratio is evidenced between second-growth hardwoods ( type E), as con- 

 trasted with a mixture of hardwoods and conifers (type EH). As the stand approaches ma- 

 turity, this difference tends to become less and less. 



One finds second-growth hardwoods predominantly used as spring nesting grounds. The 



primary reason for this is still to be determined. The presence of considerable summer food 



and the more open character of undergrowth and ground cover in this type, in contrast with 

 that existing in most overgrown lands and slashings may furnish a clue. 



Density of Undergrowth at Nest Site 



It is interesting to note from table 122* thai most birds apparently are reluctant to place 

 their nests where the undergrowth is dense. Thus we find 40.4 ])er cent of the nests situated 

 where the undergrowth is sparse and 46.4 per cent where it is medium, whereas but 13.0 

 per cent of the nests are located in dense clumps of undergrowth. 



The table suggests an interesting but not always consistent correlation between the density 

 of undergrowth surrounding the nest site and the characteristics of the woodland in which the 

 nest is found. In types where the undergrowth is normally rather dense, such as overgrown 

 land, second-growth woodland, cut-over areas and spot-lumbered woodlands, a large prepon- 

 derance of nests occupies the more open spots. Conversely, where the crown cover is hea\ \ 

 and llic undergrowth normally sparse (such as in mature hardwood or coniferous wood- 

 lands I the occasional more dense undergrowth clumps arc rather often chosen, though the 

 inajority of nests are still located in comparatively open situations. 



There is a certain, though, when recognized, not serious error, wliich is clearly brought 

 out by the above comparisons. Whereas densitv in all tvpes should ha\e been cdtniiared 

 to a single rigid standard, in realitv there was a tendency to depart somewhat from this by 

 considering tlic normal undergrowth for any type as medium. This may help to explain why. 

 in cover tvpes characterized bv heavy undergrowth, grouse were more a])t to nest in the more 

 open situations with the reverse being true in the types comparatively bare of undergrowth. 



* Sec Apprndix. p. 784, 



