Sunday, January 20, 2008

More About Bats, and Selah Winter Bird Count

A Little More About Bats

Illustration by Margie Crisp which is part of a larger illustration used on a T-shirt.Note the "free-tail" that reaches beyond the membrane.

This illustration of a bat-wing shows the arm bones and finger bones and how, with a membrane stretched across them, they form a wing. (Adapted from Bats, by M. Brock Fenton).

Photograph by M Bamberger, cropped and manipulated to bring out details in the wings

Recently, researchers who went into the Chiroptorium informed us that the wooden boxes inside the cave were full of Mexican Free-tailed bats. We knew there were bats in them, but assumed that they were Cave Myotis, another species of bats that share caves with Mexican Free-tailed bats, that frequently stay in Texas during the cold months. This is very interesting, and we are wondering if the bats have a source of food. Dr. Kunz told us he would like to come back soon and try to find out what, if anything the bats are eating. I'll include such information in a future blog when and if we find out.

The image above is a close-ups of part of an image that was in the most recent blog of January 11. Chris Johnson suggested that there might be information in the digital image that could be brought out with manipulation. So I tried, and now you can actually see bones of their fingers- which are the reason that bats belong to the order Chiroptera which means "hand-wing". Their fingers hold and shape their wing membranes, most clearly in the bat at the upper right of the picture. I am surprised by this, and excited because it was late afternoon when I took it, the light was poor, and they were flying by very rapidly. You can also see a little tail extending past the membrane between their feet, which explains Free-tailed as part of their name. Many species of bats don't have any portion of their tail extending beyond their feet.

Winter Bird Count Spots a Total of 42 Species

We held our Winter Bird Count today, which is one of three counts we hold each year and have been doing so for 7 years now. The weather is usually cold in January and we frequently get low numbers of species, especially when we have a stiff wind and/or rain. This year it was cold and windy, but clear.

The volunteer birders are led by Marsha May who is an excellent and avid birder. She is president of Travis Audubon Society, which is a big job and I have heard that she is doing an excellent job. Marsha is the person who communicates with our volunteers to let them know when bird counts are scheduled. We invite those that are interested to arrive the night before, bring a dish and join in the "pot luck" dinner, followed by a night hike, a slide show, or just sitting around the fire chatting. Bunks are available for our overnight guests in the dormitory wings of The Center.

The adventure starts at dawn, and the groups are out on their area when the sun comes up. Each group has a person who knows the ranch roads, a very good birder that knows birds by sound as well as sight, and one or two people interested in learning more about birds. We drive to interesting areas, and frequently walk to good sites. We bird until noon, when we return to The Center.

The "count-down" determines the total number of species seen and if a new species to the ranch was observed. A representative of each group indicates whether or not a bird was seen when Marsha reads the list out loud. We had five groups out on Sunday, which cover a large portion of the 5500 acres of the ranch. We look for birds in broad valleys, along creeks, lakes and tanks (Texas speak for ponds), open fields, canyons, brushy hillsides, and the flat remnants of the Edwards Plateau which are our "hill tops". Thus most of the different habitats are checked. Without exception, no one group sees all the birds that are identified during a bird count.

Below is a photograph of most of the participants, and including the two that didn't go with a group. (Margaret and J. David showed up for the count-down).

Birders for Winter Count, January 20, 2008

J. David Bamberger and our new employee in Education at BRP, Justin Duke.

Marsha May conducts the Count Down for the day.

Birds seen on 1/20/08 that had been seen on other Winter Bird Counts:
Wild Turkey, Black Vulture, Turkey Vulture, Red-tailed Hawk, American Kestrel, American Coot, Killdeer, Mourning Dove, Golden-fronted Woodpecker, Ladder-backed Sapsucker, Eastern Phoebe, Western Scrub-Jay, Common Raven, Carolina Chickadee, Black-crested Titmouse, Carolina Wren, Bewick's Wren, Ruby-crowned Kinglet, Eastern Bluebird, American Robin, Northern Mockingbird, Orange-crowned Warbler, Spotted Towhee, Rufous-crowned Sparrow, Chipping Sparrow, Field Sparrow, Lincoln's Sparrow, White-crowned Sparrow, Northern Cardinal, Meadowlark, House Finch, Pine Siskin, American Goldfinch

Birds seen that had not been seen on previous winter counts: Crested Caracara, American Woodcock, Pryrrhyloxia

New bird for Selah: LeConte's Sparrow

Photographs taken by Margaret Bamberger on 1/20/08.

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