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 July-early August period of the Monitoring Avian Productivity & Survivorship (MAPS) season is important to our annual assessment of productivity rates. During this time a critical shift occurs from the main nesting period for adults (May-June) and the post-breeding dispersal/pre-migration period (July-August). Some species are still nest building and incubating – mostly late breeders (Cedar Waxwing, American Goldfinch) and those raising second broods or first broods after nest failure. We are able to sample the year’s productivity (nest success) for many species during visits 4-7 when the juvenile or hatch-year birds are first introduced into the population.
Blue Lakes (BLAK)
On July 7 we operated BLAK for the fourth session this season. We ended the day with 13 individuals captured, all of which were newly banded. Notable amongst the birds banded were four Ovenbirds, which have been relatively scarce this year, and two adult Yellow-throated Vireos. Only two of the birds captured were young birds, a Rose-breasted Grosbeak and a Hairy Woodpecker.
Visit 5 was completed on a calm, clear mid-July morning. We were a little shocked by how quiet it was as just three birds had been captured until the final net check when a young Black-capped Chickadee was extracted from net 12. The lone highlight of the record slow morning was our second-ever Pileated Woodpecker!
Activity at MABO has been a little higher than at BLAK, although markedly less so than in previous seasons. We captured 22 birds on July 8, which was followed by a total of just 11 on July 20. We’ve banded a decent number of young birds during the two visits including individuals of Veery, Scarlet Tanager and Yellow-bellied Sapsucker, among others. Since we started in 2009, MABO has produced substantially more recaptures than any other station. So far this year we’ve recaptured 13 at BLAK, 13 at RRID and 34 at MABO.
Rock Ridge (RRID)
While MABO always seems to perform best of the three stations for adults in June, Rock Ridge typically outshines the others for dispersing adult and young birds in July and early August. A total of 13 birds were sampled on July 9, which was followed by a season-high total of 28 on July 19. This site is located on a high ridge along a peninsula that is bound by a large lake on three sides – attributes that naturally funnel birds on the move. An excellent diversity of species were detected and captured on July 19, which included a respectable number of young birds. Common Grackles, Red-winged Blackbirds and American Robins have been the primary species involved so far but this should changeover to warblers and other small passerines during visits 6 and 7, which are due in the next two weeks.
The third round of visits for the 2011 Monitoring Avian Productivity & Survivorship (MAPS) season were completed on June 27 (BLAK), June 29 (MABO) and June 30 (RRID). The weather in June has actually been rather normal and lacking in extended periods of unusual temperatures or precipitation – good for us and good for all the passerines raising young! A total of 17 (9 new, 8 recaptures) birds were captured at MABO during visit 3, the highlight of which was the second-year Sharp-shinned Hawk pictured above – a first for our MAPS efforts to date. Also of note was the recapture of five Veery from previous seasons, including three from our first couple of visits in June 2009.
The BLAK station was the “winner” of Round 3 as 25 birds (20 new, 5 recaptures) were captured here during the visit. All five recaptures were of birds banded earlier in the 2011 season. We banded a nice variety of species, including another male Black-throated Blue Warbler, a Yellow-rumped Warbler and a Hermit Thrush. The highlight though was the male Purple Finch extracted from net 7 around mid-morning – another first for our MAPS program! This species does occur regularly at all three stations but are so strictly attached to the upper canopy that they will always be only rarely captured.
Weather at RRID was calm and clear with pleasant temperatures. A total of 17 birds were sampled by our mistnet array (15 new, 2 recaptures). We recaptured a Field Sparrow that was originally banded on June 20, 2010 as an After second-year male. It’s becoming clear that the return rate of adults is very low at RRID, especially compared to MABO. Habitats and species composition differ greatly between stations, which will certainly present some interesting topics for further study once a few more seasons of data are compiled.
Here is a quick chart that describes an apparent decline of the adult population at all three stations since 2009 (Only 2010-2011 for BLAK). The graph was generated using total captures (newly banded birds and recaptures) for visits 1-4 by year and station. It would be such a tremendous resource if we had more MAPS stations across Ontario to facilitate local and regional comparisons of vital rates. Unfortunately, in marked contrast to the United States, participation in Canada and in Ontario has been very low. The development of a coordinated and standardized effort to monitor breeding bird demographics in the province would be a major asset for biologists to detect and understand forces affecting landbird populations – now more than ever with advancing climate change.
. Nidiologicals – Peck and James (1987) and Nolan,V.,Jr., E.D.Ketterson, and C.A.Buerkle (1999)
Habitat – Dry, early successional shrubland habitats ranging from pine plantations, dunes, mangroves, barrens, clearcuts and abandoned fields. Microhabitat – Cup nest usually well concealed in upper crotches of shrub Spring arrival – Early to mid May (Ontario) Average nest height – .6m-.9m Nest builder – Female only Average # of broods/season – 1-2 (variable with latitude and local conditions) Average egg laying date – 8 June-19 June (Ontario) Average clutch size – 3-5 eggs Incubation period – Average 12 days Egg colour – White to greenish white with variable brown spots, usually wreathed at larger end. Incubation – Female only Brown-headed Cowbird host – Yes
The Prairie Warbler is a rare but regular breeding species in Ontario. It is estimated that about 300 pairs occur annually in the province, although there is some evidence of recent decline due to habitat succession of granitic rock barrens along the edge of the southern shield region. We’ve been surveying and studying Prairies in Frontenac Provincial Park for the last two years and have found a small but apparently healthy population in open barrens with scattered young trees and pockets of dense shrub cover. The above photo was taken within the core breeding area, which is about 20 hectares in size and characterized by low tree cover, exposed rock, dense ground vegetation and thick patches of vibernum sp. and junipers. Most Prairie Warbler territories here are associated with sloped shoreline edges of beaver ponds and lakes, which may be a function of denser shrub growth occurring in lower lying areas.
This photo shows a typical nest site along a rocky slope where Downy Arrowwood (Viburnum rafinesqueanum) proliferates. Four nests have been found so far this summer and all but one were positioned near the top of a viburnum at heights between .7m-1.3m. All four nests have been located along slopes ranging from gentle to sharp and with no apparent preference for aspect.
Prairie Warbler nests resemble those of the Yellow Warbler (Dendroica petechia), a fairly close relative but less common inhabitant of the rock barrens. Prairie Warblers favour hot and dry environments while Yellow Warblers tend to occupy wetter shrubland habitats with a more flexible tolerance for shade/canopy closure. This nest with four eggs was discovered on June 26 when a female was flushed from a small clump of viburnum. When incubating female Prairie Warblers notoriously sit tight and only flush when very closely approached.
This is a shot of the same nest within the shrub. Prior to nest searching this season I was anticipating that Ground Juniper (Juniperus communis) would be the most common host plant for nests but it seems that the viburnums are more abundant and probably preferred here. They are a stout and sturdy shrub with woody main stems and branches, while the leaf cover provides excellent concealment and weather shielding from all sides. The only non-viburnum nest was located in a lonicera sp. that grew within a large clump of Downy Arrowwood.
Two of the four nests were found by patiently following adults carrying beakfulls of plump, green caterpillars. One of our colour banded males (nickname “Whitey”) led me to this nest with five young. Thanks are due to Julie Zickefoose for helping Seabrooke and I age these nestlings. These little prairielets were identified as being 5-6 days old and only a few days away from leaving the nest.
This female was photographed incubating on June 26. When I returned five days later I was disappointed to find that the nest had failed, probably due to predation. Common Grackles, Blue Jays and snakes would be the most likely nest predators in the barrens. I’ve twice found Ribbon Snakes (Thamnophis sauritus) above the ground within shrubs here. On the upside it appeared that the female, or perhaps a different female, was preparing to rebuild within the territory or perhaps even reuse the failed nest. The attached male (also colour banded) was singing vigorously while the female inspected forks of shrubs and called softly. On two occasions she was observed for five-minute periods shaping and touching up the failed nest. Hopefully the second attempt will fair better than the first!
Our third season of M.A.P.S is now approaching its halfway point. Our second round of visits to the three stations was a little more active than the first, especially at Blue Lakes (BLAK) and Maplewood (MABO). This striking male Scarlet Tanager (Piranga olivacea) was one of 23 birds captured on June 16 at MABO. Veery was the most abundant species captured that day followed by the ubiquitous Red-eyed Vireos – the most prolific forest songbird in the Frontenac Arch.
After capturing just 10 individuals in early June at BLAK, we expected another quiet day when we set the nets up at dawn on June 15. Perhaps the fairer weather helped as the vireos finally showed up and a bunch of other species seemed to be more evident. We ended the day with a meager but respectable 15 birds captured. Butterflies and other non-avian critters seemed to catch our attention throughout the morning, including the White Admiral (Limenitis arthemis) pictured above – a personal favourite.
There is no substitute for sitting patiently and quietly when you want to find wildlife. During our first visit a couple weeks earlier we had a Smooth Green Snake approach us at the banding station. During our next visit while I was out on a net round, Seabrooke was approached by this adult Five-linked Skink (Plestiodon fasciatus) at the station! We also had a brief look at a blue immature individual just yesterday at the same spot.
Normally I pull the plug on any planned M.A.P.S visit when the forecast indicates a 50/50 or greater chance of precipitation – too risky for me. However, I had little choice with visit 2 to Rock Ridge (RRID) on June 17. There was a brief 30 minute shower near dawn, which delayed net opening, but the rest of the morning was generally just damp and cloudy. We closed slightly early due to the forecast late morning thunderstorms – don’t want to be caught in that when a couple of kilometres out on Big Clear Lake. We noted much more bird song and chatter on this visit compared to our first but it seemed that the dreary weather was limiting bird activity. We ended the abbreviated visit with just 7 captures but left feeling encouraged by the apparent increase in numbers of expected species, particularly Black-and-white Warblers and Eastern Towhees. We caught an Ovenbird, which was weird for rock barren habitat. Even more surprising was the Prairie Warbler that sang from two positions at opposite ends of the study area throughout the morning. I’ve already picked out his colour bands so hopefully he will be there when we return….