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The Carletonian

The Carletonian

The Carletonian

    Arb Notes

    <b just had a thoroughly action-packed week. Last Friday, your arb naturalists spotted a rare wood turtle (Glyptemys insculpta) on the banks of the Cannon. The first sightings of these turtles occurred in the late nineties, with just six recorded between 1996 and 1999. We had seen none since, until this one, a young, approximately eight-year-old female. If unfamiliar with these elusive beasts, you can begin picturing them from their name, for they look like carved wood, and inhabit woods along rivers. Wood turtles can solve mazes as well as rats, and this remarkable intelligence has made them desirable in experiments and as pets. The combination of this use and habitat degradation has made wood turtles a threatened species in Minnesota. Their continued presence in the Arb bodes well for the Arb’s success as an ecological restoration project.

    A great turnout and good weather this past Saturday morning made for a successful 5th Annual Arboretum Bird Count. The objective of the bird count is two-fold: (1) to allow us to compare species’ abundances across years, and (2) to compile a comprehensive species list for the Arboretum. We obtain this data by performing one-minute point counts at 17 points in the lower Arb, during which we identify presence and abundance of all species seen and heard. The points are distributed to represent the different habitats found throughout the Lower Arb, allowing us to capture the avian diversity as much as possible. Weather can have an enormous impact on this type of data collection because both wind and rain reduce the frequency of bird song and mask its audibility. The decision to delay a count for bad weather is a tough one. Data collection should be as consistent as possible through the years to enable detection of changes, so bad weather yields a trade-off between keeping the date (migratory conditions) or weather (environmental conditions) the same. Luckily, this year we had perfect weather. We detected 66 different species, and there are even a few we know to be present in the Arb that we didn’t see on Saturday morning. While still in its infant years, the hope is that the continuation of this count annually will culminate in a long-term data set that can be used to understand the changes in migration, range and diversity in correlation with climatic and vegetation changes.

    Some fun, bright species to keep an eye out for include Indigo Buntings, Scarlet Tanagers, Baltimore Orioles, and American Redstarts.

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