| | Accession Number | 5001877 |
| | Title | Response of avian communities to forest management on Moosehorn NWR |
| | Project Description | Evidence from many recent studies indicate that populations of some neotropical migrant |
| | landbirds are declining (Holmes et al. 1986, Askins and Philbrick 1987, Holmes and Sherry 1988, |
| | Robbins et al. 1989, Askins et al. 1990). Because of the difficulty in studying populations of these |
| | birds on an international scale, the causes of the declines and the geographic area where these |
| | causes affect populations are poorly understood (Holmes et al. 1986, Robbins et al. 1989, Askins |
| | et al. 1990). Several authors have proposed that tropical deforestation has caused declines (Hutto |
| | 1988, Robbins et al. 1989, Askins et al. 1990); other evidence supports the alternative hypothesis |
| | that habitat degradation on breeding areas in North America is responsible (Sherry and Holmes |
| | 1992, Litwin and Smith 1992, Witham and Hunter 1992). Several populations of species that |
| | migrate to the Neotropics declined in recent decades within North American landscapes where |
| | breeding habitat became fragmented (Robbins 1979, Askins et al. 1990). A major tenet of wildlife |
| | management has been that heterogeneity of habitat benefits wildlife through the edge effect. Many |
| | habitat managers have broken up large homogeneous forests into patches to improve wildlife |
| | habitat for wildlife (Robbinson 1988). During the 1980s this practice was criticized. Several |
| | researchers have stated that small habitat patches are insufficient for large wide-ranging species |
| | (Blake and Karr 1984, Hunter 1987, Whitcomb et al. 1981), and that small habitat patches contain |
| | a disproportionate number of generalist species that compete with habitat specialists (Blake |
| | 1983). Nest success of many species suffers in small habitat patches because of parasitism by |
| | brown-headed cowbirds and nest predation along edges (Chasko and Gates 1982, Brittingham |
| | and Temple 1983, Wilcove 1985). Small forest fragments may not provide adequate forest-interior |
| | habitat or special micro habitats such as streams and steep slopes (Bond 1957, Whitcomb et al. |
| | 1981, Lynch and Whigham 1984). Research on direct effects of various habitat management |
| | techniques for game species on neotropical migratory birds, however, is sparse (Yahner 1986, |
| | 1988, 1991, Therres 1993). Although habitat management for game species may not be a major |
| | environmental threat to neotropical migrant populations, modifications to habitat management for |
| | game species that also benefits neotropical species would be desirable (Therres 1993). |
| | Moosehorn National Wildlife Refuge (MNWR) in eastern Maine was established in 1936 as a |
| | management area for American woodcock (Scolopax minor). The 6,580 ha area is 90% forested |
| | and has had an active program to harvest wood since 1979. During 1978-81, Derleth et al. (1989) |
| | used point counts to determine species richness and relative abundance of birds in conifer, |
| | hardwood, and mixed-wood control (uncut) and treatment (clearcut 0-8 yrs. old) sites on MNWR. |
| | Distributions of species abundance was different between control and treatment plots. Numbers of |
| | species increased in treatment plots with more species gaining rather than losing individuals |
| | (Derleth et al. 1989). Increases in estimated richness and diversity were noted in treated hardwood |
| | and mixed growth stands, but not in conifer stands. Of the 68 species of birds recorded, 17 |
| | increased in relative abundance, whereas only 2 species declined after clearcutting began. Stand |
| | treatment was associated with changes in the composition of the bird community. Derleth et al. |
| | (1989) reported that the avian community benefitted and that early-successional species did not |
| | increase at the expense of species requiring undisturbed forest. Creating small openings in |
| | continuous forest had little effect on the avian community. The refuge now contains patches of the |
| | original forest (~5,070 ha), which includes a 2,000 ha permanent wilderness area, and is |
| | interspersed with clearcut blocks and strips <15 years old (~850 ha). We censussed the avian |
| | community to determine if species richness, d |
| | Keywords | breeding bird surveys, clearcut, habitat management, neotropical migrants, songbirds, |
| | Principal | Daniel G McAuley, USGS Patuxent Wildlife Research Center: dan_mcauley@usgs.gov; Jerry R |
| | Investigators | Longcore, USGS Patuxent Wildlife Research Center: jerry_longcore@usgs.gov; |
Return to SIS Projects Listing
