2006 Field Season-March update
— 22 March 2006
— in Aplomado Falcon Restoration
Greetings from South Texas!
Paul Juergens photographs an Aplomado Falcon in flight.
Since the last update Paul and I have been busy locating territorial Aplomado Falcon pairs on and around Laguna Atascosa NWR (LANWR) and Matagorda Island NWR (MINWR), attempting to identify each individual falcon by reading their federal or alpha-numeric bands. As mentioned in the previous notes, Aplomado Falcon pairs have been difficult to track down. Many of the Aplomado Falcon pairs seem to be aloof in their territories. Many of our LANWR falcon pairs are seen together one day, then gone the next. In past years, many of these pairs were highly predictable, observed day after day not only within their defined areas but often on the same post, pole, or vegetation. The only hypotheses Paul and I can come up with is related to this year’s dry weather. Since we’ve been in South Texas, the rainfall has been minimal, and we believe it is possible that prey densities could be down this year. If this guess is correct it would explain why many of our falcons are missing from the usual areas. It is possible that the pairs are ranging within or even outside their territories in order to locate suitable prey.
The exception to this theory is the MINWR population. Paul and I spent a few days last week replacing nests in our MINWR nest boxes and locating pairs. Compared to the LANWR population, the northern group is displaying typical predictable behavior and in two days Paul and I easily located 85% of MINWR’s 13 known pairs and read their identification bands.
So what is the difference between the two populations? It’s possible that MINWR is simply more drought tolerant and is closer to an ecological constant. The LANWR study area varies in distinct ecological zones (brush, coastal prairie, human development, ranch land, etc.) while Matagorda Island is a continuous strip of similar plant and animal communities. Even when dry, MINWR (being an Island) always seems to have some moisture. As a result any given spot on Matagorda Island appears similar to the next (the only obvious exception is burned areas), so it’s possible that MINWR Aplomado Falcons are both hunting and breeding in like locations, making them easier to locate.
No matter the reason, the fact is LANWR Aplomado Falcons are proving difficult to locate this year. With this said, every day in the field we observe more falcons and, as breeding season nears more pairs are showing up at their nesting areas. To date we’ve located 27 territorial
Aplomado Falcon pairs in Southern Texas (15 LANWR, 12 MINWR.) and have identified over 60 individual falcons within the population.
Please stay tuned as we enter the breeding season.
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