Hawks Aloft, Inc.
Conservation, Avian Research, and Education
PO Box 10028 - Albuquerque, NM 87184 - (505) 828-9455

 

Up / Raptor Research / Songbird Research

Gray Vireos in New Mexico

Grey Vireo © Mike Stake

Recently, Hawks Aloft began an exciting Gray Vireo (Vireo vicinior) research project that we hope will continue and expand in future seasons. The Gray Vireo is a small migrant songbird breeding in some pinyon-juniper regions of the Great Basin. In New Mexico, it is of some conservation concern, because relatively little is known about its distribution and reproductive success.

In 2005, we located a small population of Gray Vireos in the foothills of the Guadalupe Mountains, and monitored 15 pairs. Because Gray Vireos nest only a few feet above the ground and both sexes share in nest building, incubation, and feeding, we were able to find 19 nests and learn much about their breeding ecology. We quickly found that Brown-headed Cowbird (Molothrus ater) parasitism was a prominent factor at our site. More than two-thirds of monitored nests were parasitized. Nest parasitism appeared to impact Gray Vireo productivity. Six of the 15 territories (40%) produced vireo young by the middle of July, and we documented 10 vireo fledglings (less than one bird per pair). At least one territory fledged a cowbird. Gray Vireos persistently renest after failure, and perhaps additional young fledged late in the season after we discontinued monitoring. Nevertheless, our observations indicate that productivity was relatively sparse and that many Gray Vireos require multiple attempts, thereby incurring a probable high energy cost for reproduction.

We hope to continue monitoring this population in southeast New Mexico and compare it to other populations in the state. We welcome funding opportunities that would help us expand our vireo research. Our biologist on this project has many years of experience conducting vireo research (including video monitoring) and has published multiple articles on vireo nesting ecology in peer-reviewed ornithological journals. We welcome collaboration with researchers conducting Gray Vireo studies in other regions and invite individuals or organizations to team up with Hawks Aloft.

Burned Area © Hawk Aloft

Lincoln Fire Study

In 2000, a wildfire burned portions of the Lincoln National Forest in the Sacramento Mountains of southern New Mexico.  In 2001, the Forest Service contracted Hawks Aloft to monitor avian response to the fire.  As part of a five-year study, we conduct summer and winter point counts at six sites in the forest to determine songbird use of burned and unburned areas.  Burned areas have attracted large numbers of House Wrens, Violet-green Swallows, Western Bluebirds, Hairy Woodpeckers, and Green-tailed Towhees, relative to unburned areas.  Numerous snags in the burned areas have been used as hunting perches or nesting sites for many species.  Three-toed Woodpeckers also were seen in small numbers following the fire.  Our observations indicate that the fire provided short-term benefits for some species, while some coniferous species probably lost habitat, at least temporarily.

Russian Olive © Hawk Aloft

Breeding Bird Surveys

Riparian corridors in New Mexico provide critical breeding habitat for a variety of species, including many of conservation concern, such as the Southwestern Willow Flycatcher.  Hawks Aloft is working with the Albuquerque and Taos Field Offices of the Bureau of Land Management to monitor breeding bird populations.  We survey more than one-dozen riparian sites in central and northern New Mexico each year.  Sites include a variety of vegetation types, from native trees and shrubs to exotic salt cedar and Russian olive.  Each site also has unique water flow conditions.  Annual detection rates for riparian-dependent species and species of conservation concern, associated with local conditions, will help evaluate the health and management potential for some of New Mexico's riparian sites.

Potential Flycatcher Habitat © Hawk Aloft

Southwestern Willow Flycatcher

Each spring and summer, we conduct presence/absence surveys for the federally endangered Southwestern Willow Flycatcher.  In New Mexico, annual survey sites include a canyon east of Bluewater Lake, a portion of the Rio Puerco in Sandoval County, riparian habitat near San Ysidro, and the Orilla Verde Recreation Area in Taos County.  In Colorado, we survey 10-20 sites per year in the San Luis Valley, including the entire stretch of the Rio Grande on the Alamosa National Wildlife Refuge.  Data on Willow Flycatcher use help direct management efforts at local sites.

Mountain Plover chicks © Hawk Aloft

Mountain Plovers

High arid plains in northern Taos County provide habitat for a considerable population of Mountain Plovers.  Recently, Mountain Plovers were considered for listing as a threatened species, but there is little information for populations in areas near the edge of their breeding range, like New Mexico.  For several years, we have monitored Mountain Plovers on Bureau of Land Management land between Highway 285 and the Rio Grande Gorge, in Taos County.  We document distribution of Mountain Plovers on this short-grass plain and have conducted distance sampling in an attempt to provide a population size estimate. 

Pinyon-Juniper Songbird Surveys in Estancia Valley

In 2005, we began conducting songbird point counts in pinyon-juniper and grassland habitat in the Estancia Basin, east of the Sandia Mountains.  Both pinyon-juniper and grasslands provide habitat for a unique assemblage of birds; however, pinyon-juniper habitat is widely thinned or cleared for perceived water benefits.  Our surveys in treated areas will contribute information on how different types of birds might be affected by management efforts.   

Natural Bosque Habitat © Hawk Aloft

Middle Rio Grande Songbird Study

This project is the first comprehensive replication of the avian and vegetation portions of the Middle Rio Grande Biological Survey completed in 1984.  We are sampling avian abundance and species richness relative to vegetation community and structure (C/S) types within the Middle Rio Grande Bosque.  The study area encompasses 79 river miles between the city of Rio Rancho, New Mexico, in the north, and the La Joya State Game Refuge to the south.  Within this reach of the Rio Grande, we established 46 transects representing 16 C/S types.  Ultimately, we will provide a twenty-year comparison of (1) overall change in avian

Cleared Bosque Habitat © Hawk Aloft

 abundance and species richness, (2) change in vegetation communities and structure types, and (3) comparison of current avian abundance and species richness relative to C/S types 20 years ago.  In addition, we will (4) compare current avian abundance and species richness relative to current C/S types, and (5) compare current avian abundance in relation to landscape context and amount of urbanization surrounding the Bosque.  Finally, given the extensive thinning projects being conducted throughout the Middle Rio Grande relying on the mechanical clearing of introduced, non-native vegetation, we are focusing special attention on comparing avian abundance and species richness in areas subjected to mechanical clearing to areas with a superficially similar, but naturally occurring C/S type.