Arid Lands Field Station

Ernie Valdez holding a bat. USGS photo.
Ernie Valdez holding a bat. USGS photo.
UNM Biology Department MSC03 2020
1 University of New Mexico
Albuquerque, NM 87131-0001

In The News

Wintering Grassland Bird Habitat Associations in Arizona

Thursday, March 12, 2015

FORT Research Ecologist Doctor Janet Ruth, presents results of a study of winter habitat associations in grassland birds in semidesert and plains grasslands in southeastern Arizona in her new publication: "Associations of wintering birds with habitat in semidesert and plains grasslands in Arizona," which is published in the Southwestern Naturalist magazine. Individual species were associated with various measures of vegetative structure and composition such as amount of bare ground, vertical grass density, shrub density, proportion of native grass.


Bird migration and stopover habitat use in the Southwest

To ensure full life-cycle bird conservation, we need to understand migrant behavior en route and how birds use habitat during stopover. Birds traversing the Southwest are known to use riparian stopover habitats; we know less about how migrants use other habitats and how density varies across the region seasonally and annually. Using weather radar data, we found that in fall there was greater passage of migrants through the central part of the borderlands; in spring there was some suggestion of greater passage in the eastern borderlands. Density patterns are consistent with the existence of more than one migration system through western North America and seasonally different migration routes for at least some species. Presence of bats in the data complicates some interpretations. We combined radar and land cover data to determine migrant stopover habitat use. There were significant differences in bird densities among habitat types at all radar sites in at least one of three seasons studied. Upland forest habitat in parts of Arizona and New Mexico supported higher migrant densities than other habitat types, especially in fall. Developed habitat in areas with little upland forest habitat also supported high migrant densities. Scrub/shrub and grassland habitats supported low to intermediate migrant densities, but because these habitat types dominate the region, they may support larger numbers of migrants than previously thought. This may be especially true for non-forest species. Further research is needed to address issues of target identity and to confirm the importance of these habitat types to migratory birds.

Recent Products

Displaying 1 - 4 of 4
Author Yearsort ascending Title Type Online
Bogan, M.A. and D.F. Williams
1970 Additional records of some Chihuahuan bats Journal Article N
Bogan, M.A
1972 Observations on parturition and development in the Hoary Bat, Lasiurus cinereus Journal Article N
Bogan, M.A
1975 Geographic variation in Myotis californicus in the southwestern United States and Mexico Report N
Bogan, M.A. and D.F. Williams
1975 Neotoma micropus in Chihuahua Journal Article N