SPRING / SUMMER BIRD COUNT RESUMES IN MAY

In Jefferson County, there are Bald Eagles and there are Golden Eagles. There are Red Tailed Hawks and Cooper's Hawks and Kestrels, sometimes called Sparrow Hawks. You've already noticed that there are Robins, Magpies, Bluebirds and Meadowlarks. Remember that there are owls and there are ducks. Gold stars for you if you know, or have seen a Solitaire, a Vireo, a Yellow rump Warbler or a Blue-Grey Gnatcatcher. Gold stars, if you know, or have seen, ten or twelve different kinds of ducks.

The Open Space division of Natural Resources, under the supervision of Randy Frank, has been collecting data on what birds are where, since 1993. Natural Resource Specialist Bryan Posthumus has been working with more than twenty volunteers, making regular avian surveys at several of our parks as well as locating cliff nesting raptor sites that have been noted in nine places. Some 147 species have been recorded. Since Colorado lies in the path of major migratory bird movements, many of these species are seasonal. What is of major interest to Open Space, is the relation of birds to different kinds of habitats that exist on our lands. The Colorado Division of Wildlife has published a listing of various habitats found throughout the state. The most common habitats for focused observation in Jeffco are:

Mixed Conifer - Lodgepole pine, Ponderosa, Doug fir

Meadows

General -Varied meadow, shrubs, trees

Low Riparian - Mixed shrubs, grasses along water

Mountain Shrub

High Elevation Riparian - steep slopes, fast water

Wetlands - marshy areas, seasonal drainage lands

Cliffs/Rock

Aspen

Shore/Bank - Shallow edges, lakes and ponds

Each of the surveyed parks have a specific number of locations selected where the volunteers go twice a month to observe, within a 50-meter radius, what birds are visiting that site. Fifty meters is about 150 feet, which is a fairly large circle. Originally, the observers went all year, but the observations now start in May and finish the end of July. These are the most active months when birds are mating and nesting as well as migrants coming through.

Those who are observing the raptors determine their visits by what nests are occupied or newly being constructed and then keeping watch to try to determine if eggs are being incubated and hopefully witnessing the appearance of fledglings. Some of these nests are conveniently visible from a road, but others require a lengthy mountain hike. Nests which have been monitored are: Bear Creek Park - Golden Eagle; Cathedral Spires - Peregrine Falcon; Clear Creek - Golden Eagle; Matthews-Winter - Great Horned Owl; Mount Lindo - Golden Eagle; North Table Mtn. - Golden Eagle, Red Tail Hawk, Prairie Falcon; South Valley Park - Prairie Falcon; White Ranch Park - Golden Eagle. Great Horned Owls usually nest in someone else's nests in trees but the one at Matthew Winters is located on a cliff. This writer has observed other nesting owls at Van Bibber Park, Bear Creek Park and along Clear Creek Trail in some woods a short distance east of Coors. For many years, Bald Eagles have nested at Stanley Lake, managed by the city of Westminster.

Avian Census will be continuing at Lair of the Bear, Meyer Ranch, Mount Falcon, Van Bibber and White Ranch West. Volunteers have the pleasure of being out in these parks in the early morning, witnessing the gradual greening up of the landscape as spring progresses as well as the sequence of wild flowers appearing, each in their own time. Add to that the reward of seeing some of the more colorful birds such as the Orioles, Cedar Waxwings or Western Tanagers. Their work consists of noting which birds are seen at the designated viewing sites. The temperature, cloud cover and wind speed are also recorded as well as birds seen between the sites.

Bryan works with two Natural Resource Specialists, who will be helping him with the Bird Census and the Cliff Nesting programs. Julie Simon and Ember Brignull, both with environmentally oriented degrees, will help with organizing the data and handling any necessary communications.

Time priority for Natural Resources has to do with forest management and forest management involves vegetative inventories, of our new properties as well as our existing ones. Thus, the bird data program could be considered a branch of this work and not a prime study objective in itself.

There have been some data organized as part of management activity going on at Meyer Ranch, since 1995 and continuing thru 2005. Although time spent was primarily physical work for fire mitigation, thinning of Lodgepole Pine stands, weed control, and trail building and repair. Additional bird data was continued to see if comparing the earlier '93 to '95 data showed any species decline that might be attributed to these disturbances. Of interest in this study are the methods of looking at this data. The actual number of observations and the limited number of observing stations make the numbers of birds seen rather small. A definitive study would probably require more frequent and more extensive observations

.

The methods used consisted of some comparative graphs relating to individual species and other graphs relating to grouping birds according to how and what they feed on, such divisions as nectar, insects in bark, insects in the air, seeds on trees or bushes and seeds on the ground. Further expansion, with more graphs can relate the different eating patters to each of the different habitats.

Early conclusions were not clearly meaningful and it would seem more time, letting the management dust settle, so to speak, would be beneficial in coming to any final conclusions. The changes in numbers did not indicate any drastic reduction in bird/habitat relationships. In time, with the thinning of trees and the consequent increase in open areas between trees enabling more varied plant and shrub development, a shift in species numbers would be expected.

For those working in Forest Management, meaningful change is not something that happens quickly. The factors relating to soils, rainfall, fire, and human activity all effect the balance of nature. Bryan is thinking in terms of needing fifty years! For now, we will content ourselves with what we know from the last twelve.

Natural Resources posts ongoing information on the web. Start with http://www.co.jefferson.co.us/openspace/ Or call Bryan at 303-271-5993