They aren't just "LBJs"

By way of explanation for the title ..... when presented with the challenge of identifying sparrows and other grassland birds, many people prefer to simply refer to them as LBJs (or "little brown jobs"). Identification is particularly challenging in the winter when these birds are cryptically colored, are not singing identifiable songs, and prefer to respond to disturbances by hiding in the grass or running along the ground like little mice. However, after several years of conducting research on habitat use by and effects of grazing on wintering grassland birds, I can tell you that the effort is well worth the struggle. Holding a Baird's Sparrow (Ammodramus bairdii) in the hand, with the warm ochre color washing over its face, crown, and nape, or managing a good look at a crouching Chestnut-collared Longspur (Calcarius ornatus) male coming into breeding plumage, in the split second before he bursts into the air from under your feet, is worth all the frustrations of "unknown sparrows" in between.

Over the three winters (January - March) of 1999 - 2001, I have been working on this project on desert grassland sites in southeastern Arizona, including the Appleton-Whittell Research Ranch (AWRR). I have been collaborating with Caleb Gordon (currently with the Instituto de Ecología in Veracruz, Mexico) to answer questions including:

As a group, endemic grassland birds have shown steeper, more consistent and more widespread declines than any other guild of North American bird species. Although in recent years research on the ecology of grassland birds has increased, very little has focused on grassland birds in the winter. Hence the motivation for this study.

The study was conducted on seven sites in southeastern Arizona - the AWRR, the Buenos Aires National Wildlife Refuge, U.S. Forest Service land in the San Rafael Valley, two pastures on Bureau of Land Management's Las Cienega National Conservation Area, and two private ranches (the Babocomari Ranch and the Diamond C Ranch). The study incorporated two different kinds of bird surveys in order to address the challenges of identifying wintering grassland birds. We conducted flushing line transects which involved marking a series of six 1,000 m lines at each site and then having teams of three walk along the lines, with two members of the team sweeping back and forth to flush reluctant birds. Birds were identified to species (or groups of species if that was all that was possible), and the distance from the line was recorded so that we could calculate bird density. This method is effective for species that are relatively easy to identify when they flush and which do not usually fly into mist nets, such as meadowlarks (Sturnella species), Chestnut-collared Longspurs, Horned Larks (Eremophila alpestris), and Sprague's Pipits (Anthus spragueii). Our second method was developed by Caleb Gordon for his study of winter sparrow movement patterns. We call it flush mist netting (many called it "sparrow chasing"). This involved setting up six hourglass-shaped plots of 7 hectares at each site in which 100 m of mist nets were located at the narrow part of the hourglass. We then employed groups of 15-30 volunteers to help us walk through the plots from both ends, flushing the birds into the nets. Birds were then banded and released. This method is effective for species that are very difficult to identify when they flush, such as Baird's Sparrow, Grasshopper Sparrow (Ammodramus savannarum), and Savannah Sparrow (Passerculus sandwichensis). In order to characterize the vegetative structure and composition of these sites, we conducted extensive vegetation measurements on all line transect and mist net plots, including measures of shrub density, grass height, vertical grass structure, frequency of occurrence for various plant species and species groups (e.g., exotic species, native species, forb species), and plant biomass. This will enable us to determine whether there are particular structures or types of plants that grassland birds prefer in their winter habitat.

The most enjoyable part of this project was the mist netting portion. Not only did we get to see many grassland birds "up close and personal" that few birders have seen well, but we got to work with a huge group of wonderful local volunteers who were willing to come out and tramp through the grasslands, sometimes under less-than-perfect conditions. This last winter particularly, we were grateful for their persistence since we were faced with much cold, wet weather. In fact, we had to cancel mist netting several times due to snow, high winds, or rain. Our source of volunteers included undergraduate and graduate students from the University of Arizona and other universities, local birders, "snowbirds" who spend the winters in Arizona, as well as school groups and the odd person that we picked up on the highway (well, not really, but we did get desperate a few times!). Without this great human resource, this project would not have succeeded.

The Appleton-Whittell Research Ranch was a particularly valuable site because it is one of the two sites within our study that has not been grazed for a substantial period of time (since 1968 in the case of AWRR). This will enable us to make some comparisons of bird communities and responses to habitat for grazed vs. ungrazed sites.

We have not finished analyzing our data for all three years, but preliminary analyses are already providing us with lots of interesting information about associations between bird abundance and habitat characteristics.

They Aren't Just "LBJs"

Dr. Janet Ruth (right) and a volunteer set up mist nets.

Banding a bird at the Audubon Research Ranch.

A Cassin's Sparrow in hand.