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Using trace elements to chemically fingerprint European starlings (Sturnus vulgaris) in the Okanagan Valley of British Columbia

University of British Columbia

European starlings (Sturnus vulgaris) are an introduced pest that cause significant economic and ecologic damages and losses in areas where they thrive. In the Okanagan Valley of British Columbia, Canada, a trapping program has been established in an attempt to minimize the damage to agricultural crops caused by the starling. Although over 260 000 have been trapped and euthanized the population remains stable and is thought to be increasing. As the starling is a highly mobile species it is not known where the population originates. In order to determine origin(s) of the 2010 starling population in Kelowna, a portion of the Okanagan Valley, trace element analysis was performed on six different tissue types of starlings (brain, bone, muscle, heart, liver and feathers) to determine which, if any, would be the most appropriate for origin determination. Starlings from the same location were sampled over two time periods to evaluate the degree of temporal separation provided from the various tissues. The most appropriate tissue for origin analysis will have a slow turnover time that would retain the chemical signature of where it was synthesized. As bone turns over very slowly in humans it was hypothesized that it would be the most appropriate for origin determination. Using cluster analysis bone was deemed to be the best temporal separator and the most appropriate tissue to trace origins of starlings. Bone was further examined for its ability to separate populations spatially. Bones from starlings obtained from four regions in British Columbia, and one in the United States, were analysed to create a database of source populations that the fall population of Okanagan birds could be compared to. Using principal component analysis bone proved to separate areas with high spatial resolution. All of the 2010 fall population was from immigrant sources with the majority from unknown locations. Three source populations were identified using principle component analysis by comparing immigrant birds to 95 % confidence intervals calculated around the means of each source population, proving that this technique can be applied to address small-scale movements in mobile organisms. More potential source locations are needed to characterize the Kelowna population. Trace elements proved to provide high spatial resolution, separating populations within several hundred kilometers of each other.

Text

2013-09-24

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/45121

Environmental Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/