Golden-cheeked Warbler

(photo)http://animaldiversity.ummz.umich.edu/site/accounts/information/Dendroica_chrysoparia.html

The Golden-cheeked Warbler (Dendroica chrysoparia) was listed as endangered 5/04/1990. At that time there was an estimated 2,200 to 4,600 birds left. They are endangered because of habitat loss and fragmentation. Their breeding grounds are in Central Texas on the Edward's Plateau.

(Map)http://uts.cc.utexas.edu/~gilbert/teaching/zoo369/vireowarb.html
Golden-cheeked Warblers arrive at their breeding grounds in mid-March and nest from April to May. They nest in the tree canopy at a height of 4 to 5 meters. They sit on eggs for 12 days and it takes them 9 days to fledge.

(photo) http://www.hq.usace.army.mil/CEPA/PUBS/may01/story8.htm


The Golden-cheeked warbler is also threatened by destruction of tropical rain forests. It winters in southern Mexico, Guatemala, Honduras, and Nicaragua.

Text Sources

http://animaldiversity.ummz.umich.edu/site/accounts/information/Dendroica_chrysoparia.html

http://www.tpwd.state.tx.us/huntwild/wild/species/gcw/

http://www.mbr-pwrc.usgs.gov/Infocenter/i6660id.html

http://www.cecer.army.mil/techreports/hay_warb/hay_warb-03.htm

http://www.bagheera.com/inthewild/van_anim_warbler.htm

Ash Juniper

(bird Photo)http://www.greglasley.net/gcwarblr.html

(Photo)http://uvalde.tamu.edu/herbarium/juas.htm

Ash Juniper (juniperus ashei) is a small tree which grows in the limbstone hills of the Edward’s Plateau of central Texas. Golden-cheeked Warblers are habitat specialists. They breed only in mature ash juniper woodlands. Shreded juniper bark makes up the major component of their nests.


(Photo of mature ash Juniper Bark)http://uvalde.tamu.edu/herbarium/juas.htm

Only mature Ashe juniper trees shred their bark which limits the golden-cheeked warblers range to mature Ash juniper forests. Ash juniper matures when it’s 40 to 50 years old. Between the 50’s and 70’s 50 percent of the juniper woodland was cleared for pasture. Golden-cheeked Warbers nest in stands of juniper and hardwood because they eat insects, and they need hardwood for foraging subrate during the first part of the breeding season.
(bird Photo)http://www.greglasley.net/gcwarblr.html



http://animaldiversity.ummz.umich.edu/site/accounts/information/Dendroica_chrysoparia.html

http://www.tpwd.state.tx.us/huntwild/wild/species/gcw/

http://www.mbr-pwrc.usgs.gov/Infocenter/i6660id.html

http://www.cecer.army.mil/techreports/hay_warb/hay_warb-03.htm

http://www.bagheera.com/inthewild/van_anim_warbler.htm

http://uvalde.tamu.edu/herbarium/juas.htm

The Edward's Plateau of Central Texas

(Edward's Plateau Paintin http://www.malzahnart.com/gallery.html)

The Edwards Plateau is mostly used for
The Edward's plateau is mostly limestone at elevations of 100ft to 3000ft. It lacks deep soil. It is bounded by the balcones fault to the south and east, the llano uplift, the plains to the north and the precos river.

http://www.lib.utexas.edu/books/landscapes/publications/txu-oclc-27281517/txu-oclc-27281517-201.html
(map) http://soilphysics.okstate.edu/S257/south/mlra/81.htm


(map) http://www.nmnh.si.edu/botany/projects/cpd/na/map8.htm

(Cow Photo http://waterhome.brc.tamus.edu/projects/fhsites.html)

The Edward's Plateau is mainly used for grazing cattle. Besides its shallow soil, it also has very little water making it poor land for farming.

http://en.wikipedia.org/wiki/Edwards_Plateau
http://soilphysics.okstate.edu/S257/south/mlra/81.htm

Brown-headed Cowbird Parasitism

(Cowbird Photo http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Molothrus_ater.htm)

Brown-headed Cowbirds (Molothrus ater tend to live in grasslands, so historically they didn't share habitiat with the Golden-cheeked Warbler. However, because of habitat fragmentation, cowbirds now put heavy pressure on Golden-cheeked Warblers.

(eggs Photo http://fsc.fernbank.edu/Birding/birdID/cowbird.htm)
Brown-headed cowbirds) are brood parasites. They lay their eggs in the nests of other birds. Cowbirds are obligate brood parasites which mean that they cannot build nests or raise their own young.

(Baby cowbirds http://www.berkeley.edu/news/media/releases/2004/08/05_cowbird.shtml)

All this means that the Warbler ends up raising baby cowbirds instead of baby warblers.

(Cowbird Trap http://www.griffithwildlife.com/cowbird.html__http://www.audubon.org/bird/research/)
To protect Golden-cheeked Warblers and other threatened species, managers will sometimes put up cowbird traps on the golden cheeked warblers breeding grounds. They capture and then euthanize the cowbirds. At Fort Hood military base, trapping cowbirds has produced a huge improvement in the Golden-cheeked Warbler's reproduction.

sournces:
http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/Molothrus_ater.htm

http://fsc.fernbank.edu/Birding/birdID/cowbird.htm

http://www.berkeley.edu/news/media/releases/2004/08/05_cowbird.shtml

http://www.griffithwildlife.com/cowbird.html

http://www.audubon.org/bird/research/