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The Peregrine Fund Notes From The Field
The 2003 Aplomado Hack Season
Erin Gott — in Aplomado Falcon Restoration    ShareOnce again time has flown by in a flurry of activity. Over the past couple of months the Aplomado team has been hard at work surveying new potential habitat, keeping track of breeding pairs, banding wild nestlings, documenting fledging success and starting up the 2003 hack season.

Thanks to Michael Ohlinger and Krysti Davis of Sterling Air Service, on 19 May 2003 Angel Montoya and Paul Juergens undertook an aerial survey approximately 100 miles south into Mexico. What they found were large tracks of potential Aplomado Falcon habitat starting just south of the Brownsville/Matamoros boarder and extending as far as San Fernando, Tamaulipas, Mexico. We’ve believed for some time that this southern historical Aplomado habitat could hold a population of our released falcons. The aerial survey is one step closer to investigating this possibility. During the flight our biologists locate and GPS suitable chunks of land that will later be surveyed on the ground. This is a big step in hopefully connecting our southern Texas population with the known population in southern Tamaulipas, Mexico.

Back in Texas our field team has been busy finding Aplomado nests, observing pair behavior, banding chicks, and documenting fledging. As you can imagine this is a full-time job. From January through May the Aplomado team spends 10 to 12 hours a day in the field. The countless hours spent observing the falcons give the team an insight into Aplomado behavior. The pairs are observed co-operatively hunting, nest displaying, copulating, and defending their territory together.

By late March the female Aplomado goes into an inactive pre-egg laying state usually near the chosen nest site. At this point the male becomes the food provider and nest defender. It is always amazing to see the males, who are so small with relaxed dispositions, hold such an important role in the pair’s breeding success. You cannot spend time observing these birds without becoming impressed by the male’s tenacity.  For example our FM-106 male: while reading his band in 2002 I had to get within 20 meters of him while he perched in a lone mesquite. As I crept closer and closer with my spotting scope trying to make out the tiny numbers on his #4 US Fish and Wildlife Service leg band, the little guy kept falling asleep. Every few minutes he would crack open an eye, make sure I was behaving and quickly close it to continue his siesta. I finished reading his band, turned and left without ever bothering him. Two months later I observed the same male in a burst of brilliance successfully chase and catch three Indigo Buntings (Passerina cyanea) and a White-Tipped Dove (Leptotila verreauxi) in less than one hour. That year FM-106 successfully raised and fledged three chicks, one of which we observed this year near Brownsville.

Starting in April the female Aplomado Falcons begin to lay and incubate eggs. During this time the female Aplomado Falcons become permanent fixtures in the nest; usually distinguishable only by their long tail protruding out one side of the nesting structure. The different pairs tend to have different incubating routines. Some females rarely leave the nest other than to feed, while others consistently switch out incubation duties with the male. Often the male will return with food and exchange it with the female at a designated perch. The female usually flies to another "feeding" perch, while the male flies into the nest to incubate. Once the female finishes eating, she will often take a quick flight around the nest area before resuming incubation duty.

For most pairs this routine runs like clockwork. For example our Bayside Loop pair on Laguna Atascosa N.W.R. tends to undergo this same routine every day between 0740 and 0810. This consistency helps the field team gain a greater insight into the pair’s current breeding status. For example if the Bayside Loop pair were not observed one morning between 0740 and 1000, it would give the team a reason to suspect nest failure and would lead to a thorough investigation. I am happy to report that this never occurred with our Bayside Loop pair and recently they fledged three beautiful, wild male Aplomado Falcons.

To date we have fledged 27 wild Aplomado chicks from 12 nests. We also have six nests that are still with eggs or young chicks. With a little luck these too will fledge young and add to our growing population of wild-bred Aplomado Falcons.

The big news this year is the great success of our artificial nest structures. By placing two of our new "barred" style and one of our old "open style" nest structures on tall poles, three pairs of Aplomado Falcons successfully fledged young in areas previously doomed by nest predators. It seems as though this management tool might be the answer for boosting fledging success in breeding areas that are continuously unsuccessful year after year.

It is this type of problem solving that defines The Peregrine Fund. Both in the field and at the office, those involved are always pushing for excellence. Nothing illustrates this effort better than our hack season.

This year we have two hack sites in south Texas (Goose Flats and South Padre Island, Laguna Atascosa N.W.R.) and three sites in west Texas. Our south Texas hack site attendants this year are Dianne Scherer, Lee Rindlisbacher, Jodick Perry Etheridge, and Kerry Hosken. They are a dedicated group who has already proven themselves worthy of their responsibility. To date we have released three groups of Aplomados (seven at South Padre and five at Goose Flats.)

Our first release on South Padre was hindered by high winds. Two Aplomados (male Black 5N and female Green PU) were blown off the tower and pushed over the northern dunes. I was able to locate PU approximately 1/2 mile away on the tidal wind flats where she ended up spending the night. The next morning I relocated PU and slowly herded her back to approximately 700 meters of the hack site. To our relief PU returned to the tower that afternoon and fed. Black 5N was not seen for three days and was feared dead. On the 4th day he came flying into the tower, fed twice, and slept the rest of the afternoon. Since then the other two releases have gone according to plan. As of 20 June all released Aplomados are alive and doing well.

I have always said that the success of a hack site is a direct reflection of the attendants in charge. The days are long, hot, and often uneventful, but dedicated attendants rise above the adversities to help shape the future of the Northern Aplomado Falcon

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