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Wednesday, July 20, 2011

#214 and #215

A team from Hawk Mountain visited Delaware County today to tag some vulture chicks. The photo above shows Bracken Brown with a young Black Vulture. The bird was estimated to be about 50 days old. Wing chord measurements taken of the two chicks (currently about 28-30 cm) will allow a more accurate aging. Blood was also drawn to test for lead and heavy metals, although researchers have yet to determine a normal baseline for such contaminants. Both youngsters were covered with curly brown down. Note the visible white shafts on the growing primaries. Fledging occurs 80-94 days after hatching, so these birds are only slightly more than half-way there. They are currently being fed regurgitant, presumably by both parents, one of which was sitting high in a nearby tree during the proceedings.

As Doris mentioned in a previous post, vultures are outfitted with plastic livestock tags instead of leg bands. On Black Vultures these circular tags are bright yellow. The numbers are visible on both the upper and lower side of the wing. So, this fall, if you spot #214 or #215 in the air, please note the date, time, location and behavior and report your sighting. We hope that by tagging local vultures we will be able to get a better handle on the movement of this species, particularly around the Rose Tree Park Hawkwatch area. The researchers, of course, are also interested in larger scale movements and migratory patterns. It is currently thought that family units may be maintained throughout the year. Nest sites are also re-used, so please let us know if you find one. The more birds that can be tagged, the more we stand to learn.


PS Al reports that the two young Turkey Vultures that he found, also in Delaware County, were successfully caught and tagged by the Hawk Mountain team. They are numbers 312 and 313. Turkey Vulture wing-tags are blue. Please also report any sightings of these birds.

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