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!
The search for new MAPS sites to join our existing Maplewood Bog and Rock Ridge stations has begun. The process is challenging, particularly here in the Frontenac Arch where ‘disturbed’ habitats with pronounced edges can be hard to find. The edges are important as this is where adults and young congregate during post-breeding dispersal, which is key to evaluating annual productivity. The heavily forested Frontenac region also tends to feature open understoreys with little shrub or sapling growth – not suitable for capturing birds using mistnets. Therefore the search feels something akin to looking for a needle in a haystack: a daunting job, to be sure, but not impossible. A needle we shall find!
Ontario Parks has been a tremendous supporter of FBS and have made a number of useful site suggestions for a second MAPS station within park boundaries. I will be checking out these various sites and will report on them as they are visited. I searched a good candidate site in a small portion of Frontenac Provincial Park today but unfortunately found nothing suitable for a MAPS site. Despite this I did have an incredible outing with some noteworthy discoveries.
Today’s meander took me through a patch of mixed forest dominated by Eastern White Pine. Ruby-crowned Kinglets, Pine Warblers and Yellow-rumped Warblers were numerous in the canopy while newly arrived Eastern Towhees called from small rock outcrops. I came upon this excavation that was recently created by a Pileated Woodpecker, a common inhabitant of Frontenac Park. The sap was running quite thick and apparently attracted and drowned a considerable number of springtails along with a few other insects.
I spent an hour or two exploring the margins of many small/medium wetlands for good edge habitat but managed to find nothing of any use to a would-be bird bander. I did, however, find an impressive showing of early spring wildflowers such as Trout Lilly, trillium, hepatica, Bloodroot, Dutchman’s Breeches and Spring Beauties. After snapping a few photos, I decided to head for an area of mature forest en route back to the main road.
This is when things got interesting! This Red-shouldered Hawk nest was rather easily discovered in a mature Yellow Birch within a steep valley of mature hardwood forest. The adults were nearby and quite displeased with my presence! This is the first nest found by FBS in 2010, which is consistent in habitat and timing with the first nest of 2009 – a Red-shouldered Hawk nest on Canoe Lake Road. I quickly left the nest site to avoid unnecessary disturbance to the hawks, which seemed to be in the beginning stages of nest renovation.
There is a considerable amount of mature deciduous forest in Frontenac with some century old stands present. These forests are ideal for several species of conservation concern such as Cerulean Warbler and Red-shouldered Hawk. However, the ‘real’ biodiversity in these forests is exhibited by its plant and insect communities.
With forthcoming Louisiana Waterthrush surveys in mind, I ambled down the bank to check on the water level and flow of this stream that courses through the forest. This past winter was the driest in decades and the lack of spring rainfall has further compounded the dry conditions. The result is very low water levels and weak flow of many streams in the park. I am hoping that we will get some decent rain in the coming weeks as the current picture for breeding Louisianas is bleak. There will be more to follow on our efforts to inventory the park’s streams for Louisiana Waterthrush.
The stream valley was hopping with early spring activity and the most apparent of the beasts were these ghostly-white butterflies, which I suspected might be West Virginia Whites (Pieris virginiensis), a species of Special Concern in Canada. An impressive number of these eye catching butterflies were observed fluttering about near the forest floor. This species is known to occur in Frontenac Park where suitable habitats are found. West Virginia Whites occur in mature moist deciduous forests in isolated pockets of southern and central Ontario. They are known to occur at about 50 sites in the province and were once classified as an Endangered Species (1977). The West Virginia White is one of the earliest butterflies to emerge in spring when the adults seek out emerging toothwort, which their larvae feed on exclusively. I will be watching closely for this species during all of the work in mature forest coming up in May.
Often one finds the most interesting things when looking for something else. The search for new MAPS sites will continue……