~~Elphick Lab-UCONN Ornithology Group~~


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Department of Ecology and Evolutionary Biology, University of Connecticut

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Female Saltmarsh Sharp-tailed Sparrow with radio transmitter (left). Overlapping spatial use by a female (blue) and her fledgling (red) simultaneously radio-tracked over a 21-day period.

I attach small radio transmitters (the size of your pinky fingernail) to an adult female and to one of her nestlings. Some of these nests occur in very large salt marshes ( East River, CT) and some of them occur in very small marshes (Indian River marsh, Clinton, CT). Everyday I find the radio-transmittered female and fledgling at the same time and record their location (using GPS) and the characteristics of the immediate vegetation. Using spatial statistics I test the relatedness of the female and fledgling movements as the fledgling gets older and less dependent on mom for food. By recording fine-scale habitat characteristics I am able to test if certain plant species or patterns of plant species influence the movement of both individuals. This is especially important for the young birds, since they have to push their way through the vegetation until they can fly.

Saltmarsh Sharp-tailed Sparrows only nest in salt marshes along the eastern US coast. Salt marshes have the misfortune of occurring where people also enjoy occurring. Not surprisingly, many of the salt marshes in New England have been built upon or their tidal dynamics have been severely altered to the point where the natural salt marsh vegetation cannot exist anymore. These salt marsh plants are quite sensitive to changes in salinity, which occurs when the marshes are blocked off from the tide by roads and culverts.

Saltmarsh Sharp-tailed Sparrows are listed as a Species of Special Concern in Connecticut because of their specialized habitat requirements and occurrence of this habitat along a narrow strip of land only along the coast. The males of this species provide absolutely no parental care. Saltmarsh Sharp-tailed sparrows eat a lot of insects during the summer and get around the salt marsh by walking and running a lot through the vegetation. In some Saltmarsh Sharp-tailed Sparrow populations (like the ones I study) most of the nest failure is caused by high tides and the subsequent drowning of young in the nest. You could say that these nestlings are in an evolutionary race to get out of the nest as soon as possible, and they grow quite fast. They leave the nest 10 days after hatching, before they can even flutter.