Great to be back in Frontenac this week! My first memorable observation of the season was of two black bears encountered along Devil Lake Road on an early morning commute – interesting start. This week I began revisiting stream and swamp woodland sites for Louisiana Waterthrush (Parkesia motacilla). This will be our third and final season of inventory and monitoring for this species of concern. In spring 2010 and 2011 we emphasized the maximization of coverage for potentially viable breeding sites in the study area. We have a handful of hitherto unexplored locations to check this year but most of our available time in May will be dedicated to historically occupied sites to procure assessments of breeding status in 2012.
These West Virginia Whites (Pieris virginiensis) have been faithful companions on my travels to mature forested ravines and swamps in the region. Once considered a Species at Risk, they remain quite rare, known to occur in only about 50 sites in Ontario. They are common in Frontenac Provincial Park on warm days in April and May. West Virginia Whites are threatened by habitat loss and the invasive Garlic Mustard (Alliaria petiolata), which is a close relative of their host plant, the Toothwart (Dentaria diphylla). Adults will lay their eggs on Garlic Mustard but the hatched larvae will not feed on the invasive plant and perish.
The birding was excellent this week thanks to the recent warm front. Cerulean Warblers were particularly numerous. Eleven males were counted en route to one of our Louisiana Waterthrush sites. Over the years I’ve amassed an impressive collection of hopelessly blurry photos of Ceruleans or the perches they left behind. This is the best I’ve managed to come up with so far – sadly. It was pleasing to find that Louisiana Waterthrushes have returned to the breeding site we first described in 2010! A pair has been detected here for three consecutive years, which makes this site in Frontenac Prov. Park one of just a few annual breeding locations in the region. High fidelity to these sites make them important “footholds” at the range limit where contraction and expansion can be marked. These Frontenac louies are true pioneers!