Friday, November 6, 2009

News from the Field

What does a Field Studies Team do?

2009 has been a very busy year for World Bird Sanctuary’s field studies team.  Our longest running field studies project with Ameren UE is our nestbox study.  The nestbox study looks at power line cuts and the methods of control used on the vegetation.  We then compare the methods of control with nestboxes that are placed on these lines and at how successful the nestboxes are for cavity nesting species, such as Eastern Bluebirds, Tufted Titmouse, Carolina Chickadee, House Wren, Carolina Wren, and a specialty Great-crested Flycatcher.

On each stanchion that we check we have two Peterson nestboxes and two standard nestboxes.  The different nestboxes are preferred by different species, these boxes are built by eagle scouts as part of their eagle scout projects.  Our field studies staff, including Trina Whitner, Matt Sheele, and myself check the three lines.   Each time we check the boxes we record in which box we find eggs, babies, babies banded, and then number that fledge.  This data helps us to determine just how successful the control methods are.

 In addition to checking the nestboxes we also perform point counts at select locations on each line.  Two trained naturalists count all of the birds they see and/or hear in the area for ten minutes.  This additional data helps us to determine how the control methods affect other nesting birds in the area.

This season was the fifth year in a five-year study with Ameren looking at the treatment methods used on power cuts to determine which of their control methods is the best for nesting bird species in the region.  This year we found that the number of boxes used was way down. Out of the 309 boxes installed over three lines only 64 were used.  Even the number of young that fledged was down.  We feel that this was due to the fact that over the last few years we have had unusually high rainfall that increased the amount the vegetation grew between the treatments. Vegetation in many cases was above 5 feet.  Bluebirds and other cavity nesting species do not like vegetation this high, especially around the nest boxes. 

At this point in the study it is still too early to draw any firm conclusions.  There are few consistencies in the data from 2005 to 2009, and it will take several more years to see the development of any real pattern.   For this reason we need to continue this project to determine whether the height of vegetation is a major factor, or if  there are other environmental factors that led to the decline in birds this year.

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Submitted by Cathy Spahn, Field Studies Coordinator

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