May 18, 2011

Geolocator tags, 5 and counting

In February 2010 ~33 geolocator tags were harnessed (with Kevlar string, making sort of a backpack) to wintering golden-crowned sparrows here at Palo and a near by location. In June 2010 35 tags were attached to breeding Swainson's thrush between three sites (Palo, Pine Gulch, and Muddy Hollow).

Here's a short description (from the seller) of what the tag's function:

"Our light level geolocator is an instrument used to record the flight paths of migrating animals; particularly birds. British Antarctic Survey (BAS) engineers originally developed the instrument for recording the behaviour of the Wandering Albatross. The device records the change in light levels at different latitudes and longitudes, enabling scientists to determine where the bird has been. Animal recapture is necessary to retrieve the device as it is an archival logger. Information is recovered by downloading the data from the logger for analysis. Using low power technology and data compression the device is able to record data for many years."

In the fall we retrapped ~11 sparrows that were fixed with tags, but only retrieved the low number four tags, as we ran into the problem of tags having been bitten off by the strong seed-crushing sparrow bills...sad, indeed.

Within the last three weeks we have seen the arrival of the Swainson's thrush and have since retrieved 5 tags! Three at Muddy Hollow (one today!), one at Palo today, and our first at Pine Gulch. It seems as though the tags have stayed on these birds much better, and it makes sense, as their bills are much better fitted for picking at insects and eating berries. It's pretty exciting to know that there are still 30 tags out there and we are seemingly likely to get many more.

After returning to the banding station with the bird in a bag, Amanda and I decided to play it safe by removing the tag from within the confines of my car (in case there was an accidental release)...

Excitement
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Swainson's thrush with one color band and one silver
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Attached geolocator
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Cutting the tag off
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Success!
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2 comments:

  1. how is the geolocator attached?>??

    ReplyDelete
  2. with Kevlar string, making sort of a backpack

    ReplyDelete