Structural Characteristics of Blue Grouse Territories in Southwestern Montana

Structural characteristics of male blue grouse (Dendragapus obscuruspallidus) territories and their relationship to land-use practices and forest succession were studied from 1967 to l969 on a 700acre area of Sapphire Mountains in southwestern Montana. During 130 observation trips, 1,010 sightings of males on 40 territories were made. About 60 percent of males were leg-banded for individual identification. Vegetation and physical characteristics were recorded for 27 territories where males were obsewed 14 or more times. Territory size averaged 2.0 acres. Thickets of coniiferous trees, major vegetational component of territories, averaged 0.2 acre and provided about 675 feet of edge. Ite density of thickets averaged about 1,200 trees per acre. The average diameter of trees in thickets was 4.9 inches. Most trees in thickets were from 10 to 60 years old. Thickets comprised mostly of Douglas-fir ( Pseudotsuga menziesii ) were generally of greater density and smaller total area than those comprised largely of ponderosa pine (Pint4s ponderosa ) rrhe longevity of thickets used by males was apparently about 40 to 50 years. Territories that were occupied intermittently during an 8-year known history averaged 2.3 acres; those occupied continuously averaged 1.8 acres. Discriminant function analysis indicated that territories could be distinguished from unused areas with a high degree of success ( 96 percent) when 10 variables were used. Breeding habitat was associated with a ponderosa pine-fire successional stage in Douglas-fir vegetational zone and with young climax stages in both ponderosa pine and Douglas-fir vegetational zones. Objectives of study were to determine structural makeup of territories of male blue grouse and to evaluate effects of forest succession in relation to silvicultural practices on blue grouse breeding habitat in ponderosa pine and Douglas-fir vegetational zones. A small area of Sapphire Mountains in southwestern Montana was chosen for a quantitative study of vegetational characteristics of territories of male blue grouse because of known history of approximately 40 different territories. Also, a large proportion of territorial males had been leg-banded for individual identification. Structural characteristics of vegetation found at territories of male blue grouse have been discussed by several different authors but not in a quantitative manner. Bendell and Elliott ( 1966:439, 1967:24) 1 A joint contribution from Montana State University, Agricultural Experiment Station, Project No. 409, Paper No. 2S2 Journal Series and ie Game Management Division, Federal Aid Projects W-91-R-10 through 12, Montana Fish and Game Department. 498 noted that the position of territories in dense cover may depend upon location of openings. Other auiors ( Blackford 1958: 146, Mussehl 1962:1 ) have described territories in open areas as being associated with thickets of coniferous vegetation. Forest succession, after fire or logging, may act as a control on density and positioning of territories (Mussehl 1962:5). Breeding blue grouse accept a variety of different forest types, from moist forests in Pacific Northwest to relatively dry forests of interior Rocky Mountain region. Fulltime field studies were conducted from late July to late August 1967, from mid-April to mid-September 1968> and from early April to early September 1969. I thank Dr. R. L. Eng, Montana State University, for technical supervision and guidance in preparation of manuscript; T. W. Mussehl, Montana Fish and Game Department, for initial project planrling, advice, and assistance; P. Schladweiler, Montana Fish and Game Department, for advice and assistance; and L. J. Lyon InThis content downloaded from 157.55.39.116 on Sun, 18 Sep 2016 06:39:15 UTC All use subject to http://about.jstor.org/terms BLUE GROUSE TERRITORIES IN MONTANA * Martinka