FBS Focal Species « Frontenac Bird Studies

July 4, 2011 • 11:12 am 1

the Nest Files – Prairie Warbler

Adult male Prairie Warbler (D.Derbyshire)

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Prairie Warbler (Dendroica discolor)

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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

Prairie Warbler habitat (nest site in foreground)

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.

Shrubs along rocky slope (nest site in foreground)

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 Nest with eggs

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.

Nest in viburnum

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.

Prairie Warbler nest with five young (5-6 days old)

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.

Incubating female

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!

Filed under: Nest Monitoring, News, Prairie Warbler, the Nest Files

June 23, 2011 • 7:24 pm 1

Report on Frontenac Biothon 2011

Six-spotted Tiger Beetle (Seabrooke Leckie)

The second annual Frontenac Biothon was held on June 11-12 in various locations at Frontenac Provincial Park. The inaugural biothon in 2010 was a terrific event – full of interesting observations and we raised some much needed funds for Frontenac Bird Studies at the same time. Last year we compiled a total of 441 species, just shy of our target of 500 for the 24-hour blitz. This year we took to the park with a handicap as our plant guru was home with a recently hatched baby girl! We knew we had to step our game up and I’m happy to report that we did just that.

The 2011 biothon was a sort of grand tour for three of us. Chris, Steve and yours truly logged over 22 kilometres of hiking in just over 24 hours. We visited the abandoned farmlands and rock barrens in the park’s southeast corner, traveled some of the park’s main artery along Big Salmon Lake and also biothoned the length of Moulton Gorge, which took us to the mature forests of the park’s northern region.

Rock Barrens near Flagpole Hill (Derbyshire)

All the effort paid off as we visited some markedly different zones. In the rock barrens we found unique plants and insects, Prairie Warblers, a Sandhill Crane and a singing Yellow-bellied Flycatcher. The crane and the flycatcher were highly unusual summer records for the park!

Waterfall near Moulton Gorge

The mature forests were a little more comfortable for hiking due to the shade and cooler temperatures. The diversity here was very high. The highlight for me was the Woodland Jumping Mouse that we startled near a waterfall – a fantastic creature. The excursion concluded with the observation of Cerulean Warblers and Louisiana Waterthrushes feeding young – two Species at Risk successfully raising young within 75m of eachother!

Meadows south of Slide Lake (Derbyshire)

And finally, actual meadow habitat! Lush wet meadows are very rare in Frontenac Provincial Park as nearly all of the abandoned homesteads and farms have returned to forest. The plant and insect life in these meadows south of Slide Lake was exceptional. It was great to have Chris and Steve there to help me sort through the all the non-avian species. Indigo Buntings and Chestnut-sided Warblers seemed to be most abundant during our stay but I’ll have to return another time for a more thorough search for grassland bird species.

Meanwhile, during all of our exhaustive hiking and paddling, Seabrooke was quietly racking up nearly 350 species just at her station near Campsite 6 on Little Salmon Lake! Seabrooke probably considers herself an insect specialist but is a very well-rounded naturalist, too. By the end of the biothon we had recorded 166 species of insects. Dragonflies and butterflies were much more evident this year than last and we still managed to ID a small selection of nocturnal moths despite the wind and rain that moved in during the evening of 11th. Our totals were a little higher for all taxa in 2011 with the exception of moths and fungi/lichens. The lower diversity in both of these groups is due to weather (moths) and event timing (fungi). We are still working on a few identifications but at present our total for Frontenac Biothon 2011 stands at 468, which is 27 species higher than last year. While not quite the 500 mark, our list for 2011 was quite an achievement given that we were missing a key team member and that the weather severely limited our mothing production. Much like our biothon from a year ago we found some truly great stuff, had an adventure and supported the FBS program to boot – all things that make the biothon a great event!

On behalf of the Migration Research Foundation I wish to extend our thanks to this year’s many sponsors who donated to the three biothon teams. Of course, the whole event would not have been possible without the efforts of our dedicated volunteer biothoners; Chris Dunn, Steve Gillis and Seabrooke Leckie! Lastly, thanks to the following Ontario Parks staff for their continued support of Frontenac Bird Studies and the Frontenac Biothon fundraiser; Corina Brdar, Peter Dawson and Bert Korporaal.

Below is a small selection of species recorded during this year’s biothon – hope you enjoy!

Prairie Warbler (Chris Dunn)

Sawfly larvae (Seabrooke Leckie)

Silver-bordered Fritillary

Harris's Checkerspot (Chris Dunn)

Filed under: News, Prairie Warbler

June 7, 2011 • 8:53 pm 0

Prairie Warbler colour banding begins

Male Prairie Warbler (Dendroica discolor)

It will have to be another brief update for today. I suspect I won’t be back to more lengthy writings until late June or early July when things begin to ease up – I’m pretty swamped with fieldwork right now. One of the major tasks at hand is our continuing studies of Prairie Warblers in Frontenac Provincial Park. After 13km of combined paddling and hiking I managed to capture and band one of the isolated males this morning!

Most of the Prairie Warblers occupy the most barren of the rock barrens and are loosely colonial but there are a few singletons holding court in smaller patches of suitable habitat. This particular individual is maintaining a territory about 3km away from the core breeding area. His territory is quickly regenerating and it is possible that the habitat will become unsuitable within the next decade due to natural succession. It seems that some individuals have already abandoned this neighbourhood as the scrubby ridge formerly hosted as many three males as recently as 2009. Fortunately the “core” breeding area is very much intact and will remain so for many years to come. Below is a photo depicting the territory of the above male. Stay tuned for more updates…

Filed under: Prairie Warbler

May 23, 2011 • 11:19 am 1

The Louisiana and the Cerulean

This video was recorded yesterday while revisiting the site where a Louisiana Waterthrush nest was found on May 26, 2010. The stream at this site is flowing with so much vigor that the two waterfalls severely limit the audibility of my playback system. Despite this I was able to locate a territorial male at the south end of the stream complex in a low valley sandwiched between two small ridges. I promptly ended playback as soon as the male responded and watched him for about ten minutes or so as he moved back and forth from the stream to higher perches. At one point he moved higher toward the canopy and was instantly chased off by a bill snapping small passerine, which turned out to be a female Cerulean Warbler (Dendroica cerulea). I followed the female for several minutes and hit an ornithological jackpot of sorts when she flew to a nest located on a horizontal branch of a large Sugar Maple (Acer saccharum), about 15m above the ground.

Cerulean Warblers build their nests high in the upper canopy of deciduous forests that have mature trees, little or no understorey and small gaps or breaks in canopy closure. These characteristics make their nests quite difficult to find and even harder to inspect and monitor! In this case I was able to get a decent view of the nest from either of the two ridges, which put me roughly 15 feet closer to the crown of the large trees growing in the valley. Even with this advantage I still had to zoom to 39x to get a low quality recording. Gotta thank the 749 mosquitoes for all the shakiness. I will definitely be returning to this site (with a tripod!) to monitor both of these important breeders in the next several weeks. Frontenac Provincial Park is one of the most significant protected areas for Canada’s population of Cerulean Warblers now listed as an Endangered species by COSEWIC.

Playback and Bullfrog at the falls

Back to the waterthrush surveys. Things have picked up a bit since my last post but it seems that 2011 will be marked as a down year for breeding Louisiana Waterthrushes in this region. I have not been successful at several reliable sites despite as many as four repeat visits. A review of historical records show some evidence of a downward trend occurring since the first half of the last decade. Despite an apparent population decrease coinciding with the initiation of our study in 2010 it is critical to monitor the sites through the good times and the bad times. Interestingly, the high number of unoccupied sites found this year has only buoyed my interest in the study going forward. Also, the 2011 season is not over yet as surveys at five more sites are yet to be completed and I do have four active sites to keep tabs on.

Ferns and Jack-in-the-Pulpit

Gorge near Birch Lake

Deer Fly season begins

Filed under: Cerulean Warbler, FBS Focal Species, Louisiana Waterthrush, Nest Monitoring, Videos

May 13, 2011 • 4:13 pm 1

Where art thou Parkesia Motacilla?

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[ Note that Louisiana Waterthrush (formerly Seiurus motacilla) was recently moved to the new genus Parkesia with Northern Waterthrush, which leaves Ovenbird as the only remaining Seiurus species ]

There has been lots of noteworthy observations in recent days but the most significant development continues to be the late arrival of spring and apparent scarcity of Louisiana Waterthrushes in the study area. The mass of ice pictured below was found yesterday near Little Salmon Lake, Frontenac Prov. Park – a late spring indeed. I’ve now surveyed 23 streams and creeks in and around Frontenac Provincial Park with only a few sightings of the target species to show for it. As the above video shows the sites are in excellent condition owing to high precipitation in late winter and early spring. Water levels and flow are higher than a year ago and insect forage is abundant (particularly the black flies!). Click here for a larger version of the clip.

Lingering ice under cedars

Range Map (Cornell Lab of Ornithology)

The Louisiana Waterthrush has a very limited range in Canada. Breeding occurs primarily in Southern Ontario where remnants of mature deciduous and mixed forest remain. Looking at the map above, the small green dot at the east end of Lake Ontario indicates a cluster of breeding sites corresponding to mature woodlands of the Frontenac Arch and Thousand Islands. There is evidence that this species is expanding northward probably in response to maturing and regenerating forest cover since the logging boom of the 1800s. The population in the Frontenac Arch is essentially the northernmost outpost for this species in North America and somewhat disjunctive from the core range. It has been suggested that Ontario’s population is dependent upon immigration from the source population further south and could therefore be subject to more variable rates of fidelity and productivity. Perhaps 2011 will be a down year for our north-wandering pioneers? We still have a few weeks of surveys to complete and will have a much better handle on the situation by early June – I have a good feeling that results will improve.

Little Salmon Lake

The Louisiana Waterthrush recon work took me to a network of streams flowing to and from Little Salmon Lake in the park’s interior. There are some very promising sites in the area but the relatively young age of the forest is probably not suitable for the species at the present time. Regardless of whether the birds are there or not the effort is still worthwhile to describe and index potential breeding locations for the future. This was my first foray into this area, which made for an interesting day. Sandy beaches like the one pictured above are very scarce in the park.

Pickerel Frog on the beach

The only sunbather I found was this Pickerel Frog (Rana palustris) – a nice find. While not exactly rare they are uncommon compared to their close relative, the very similar and more numerous Northern Leopard Frog (Rana pipiens). Pickerel Frogs are always brown in coloration and have squared spots aligned into two neat rows down their backs. The Northern Leopard Frog is usually green, although sometimes brown too, but have circular, more randomly distributed dark markings.

Filed under: Breeding Bird Studies, Louisiana Waterthrush, Little Salmon Lake, Pickerel Frog