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

Female LOWA entering nest

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Louisiana Waterthrush (Seiurus moticilla)

Nidiologicals – Peck and James (1987) and Douglas Robinson (1995)

Habitat – Gravel bottomed streams flowing through mature deciduous or mixed forest. Also nests in wooded swamp habitats on occasion.
Microhabitat – Nest built in cavities of stream banks, upturned tree roots or fallen logs.
Spring arrival - mid to late April (Ontario)
Average nest height – 0m (always nests on the ground)
Nest builder – male and female
Average # of broods/season – 1 (multiple broods not reported)
Average egg laying date – May 3 – June 12 (New York)
Average clutch size – 5 eggs
Incubation period – average 13 days
Egg colour – Whitish, spotted or blotched with ruddy brown, usually concentrated at large end
Incubation – female
Brown-headed Cowbird host – yes

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Nest building in progress

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Another FBS first – a Lousiana Waterthrush nest! A territorial pair was first located on May 10th at this site but no further breeding evidence was obtained at that time. A followup visit on May 20th revealed both the male and female building this nest in the stream bank above a waterfall. So why the delay? It’s possible that an earlier nest was abandoned but it is more likely that nest construction was delayed after the pair bonded, which is typical according to previous studies (Robinson 1990). On May 20th the pair were observed entering the nest site, which at that time was bascially a mud bowl with a bulky leaf exterior.  The pathway of leaves visible here is a common feature of a Louisiana Waterthrush nest but is not always built. The above photo illustrates this ‘pathway’ constructed of dead leaves, which are noticeably damp and likely collected from the water. The wet leaves and the addition of mud are probably used for adhesion and support of the nest exterior and pathway.

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Nest complete with eggs

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There were four eggs in the nest this morning, which suggests that egg laying began by May 22nd at the latest (1 egg is deposited per day). There might be one more egg still to come as the average clutch size is five (Bent 1953). I watched the female incubate for about an hour before she slipped away for a break. The male was present, he sang on two occasions nearby and made short excursions to the waterfall but never approached the nest. With the female on break, I approached the nest to check its contents and snap a few quick photos.

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Nest contents

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The interior of the nest had transformed since my last visit. What was formerly an excavated mud bowl had become a neatly constructed cup nest lined with fine grasses, rootlets and animal hair.

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This last photo shows the nest site context. This would be considered a fairly exposed nest site for the species. This spot wasn’t on my radar during my initial scan of the banks along the waterfall. There were several other sites that would have been more enclosed, shaded and difficult for non-avians to access. You can just barely see the stream bottom in the lower left corner. Luckily, relocating this nest has always been instantaneous thanks to the convenient tree root pointing to its location! Waterthrushes never fly directly to their nests, instead, they approach the nest by walking from a distance as great as 10m – very typical behaviour for ground nesters. This is nicely demonstrated by the following video of the female at the nest from this morning – whom I could have watched for hours if not for the oppressive heat today. If all goes well, the eggs will hatch in 8-10 days and I’ll be back to check on the family in early June.

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Finally, here is a short video of an adult female LOWA at the nest from today’s visit. Just to avoid any confusion, I should mention that during the video you might hear a Northern Waterthrush singing nearby. The two waterthrush species “get along” very well and exhibit little or no interspecific aggression (Craig 1984). The video can be viewed at higher resolution here.
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Common Loons (Big Salmon Lake)

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At nearly five kilometres long, Big Salmon Lake is the largest lake within Frontenac Provincial Park boundaries. The lake has over fifteen kilometres of shoreline and has a maximum depth of 42.3 metres. Bisecting the park along a northeast-southwest axis, Big Salmon has long been a gateway to the Frontenac backcountry and a focal point for early mining and logging industries. Geologically, the lake also marks a divide between two distinct zones – granitic gneiss and marble to the northwest and a large dome of diorite in the southeast.

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Yesterday, I ended up paddling the entire length of Big Salmon to reach two remote streams for the ongoing Louisiana Waterthrush inventory. This long oligotrophic lake was absolutely stunning and a joy to travel across. Steep cliff faces with ancient bonsai-like conifers, Cerulean Warblers singing from mature oak-maple canopies and windswept white and red pines on small rocky islands were just a few of the highlights during the trip.

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Canadian Tiger Swallowtail and Juvenal's Duskywing

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The sightseeing was a nice diversion but my main priority was to find two streams, which to me were nothing more than tiny blue lines on a map. I’ve visited fifteen streams so far this spring and never really know what I am going to encounter. Some streams are pristine, fast moving waterways in steep sloped ravines while others are completely dry and sun drenched. Regardless of their condition, the purpose of the project is to index as many sites as possible to evaluate current stream conditions, habitat preferences, aid future inventories, and to model population parameters of Louisiana Waterthrushes in the area.

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This particular stream was an absolute gem and ‘ticked all the boxes’ for Louisianas in terms of aquatic characteristics as well as slope, canopy closure and presence of suitable nest sites. The meandering stream was teeming with life. My survey of its length revealed a considerable forage base for waterthrushes and very high biodiversity with one glaring exception – no Louisiana Waterthrushes! There was no response to playback following an unsuccessful ground search for the species. This was surprising at first but a broader scan of the site indicated that the mature forest shading the stream was a relatively small patch bordered by younger growth and even small rock barrens. Louisiana Waterthrushes are area sensitive and therefore need large contiguous tracts of mature forest to breed, which would make this site unattractive. Forest succession might make this site suitable for LOWA in the not so distant future.

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The stream itself has been around for quite awhile, evidenced by the erosive passage of water over and through the rocks of the stream. The rectangular finger-shaped rock on the right in the photo above has water passing through it and looks oddly man-made. I’ve uploaded a short video clip of this interesting feature below.

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Green Frog

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Last but not least, a Green Frog (Rana clamitans), one of the many inhabitants of the stream. This fellow was sitting in the middle of the watercourse, faced upstream. Maybe this frog is just chillin’ but I think this might be an excellent way to catch some lunch – let the stream bring it right to you.

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I am starting to run out of accessible waterthrush sites but still have a few more left to visit before the whirlwind of our other breeding bird work begins in early June. I will miss these shady ravines….

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CLICK HERE to watch this video in High Definition on Vimeo

The above video was captured over a period of four and a half days from June 27-July 1, 2009. A female Red-eyed Vireo began installing the foundation of a nest in a young maple about two meters above the ground on June 27. The process in its entirety was fascinating to observe as the footage revealed subtleties of technique and the use of various materials.

The Red-eyed Vireo (Vireo olivaceus) is one of the most common passerines of eastern forests in North America. A neotropical migrant, “Red-eyes” migrate to South America each autumn where they feed primarily on fruit. During the summer they are dedicated insectivores of mainly deciduous forest stands and fragments. The male Red-eyed Vireo is a vocal standout in the avian world as they hold the record for most songs per day of any bird species on the planet. In June and July the female Red-eyed Vireo builds a pensile or suspended cup nest from an outer fork of a branch-exclusively in deciduous tree species. The subject nest of this writing matches this description very closely. This particular nest was easily accessible for monitoring, providing a convenient window into the meticulous and masterful work of the nest building songbird.

I strongly recommend that you watch the HD version of the video to see the subtle movements and to appreciate the remarkable precision of the bill in manipulating nest material. The video clearly shows how important spiders and their webs are to nest construction for this and many other bird species. The female worked constantly during daylight hours over the course of four days. Review of the footage indicated that she visited the nest for periods of between three seconds to two minutes with an average of four minutes between trips. This rate would mean that just shy of 200 visits to the nest are made each day for a total of ~850 visits to complete a nest in four to five days!

Eastern White Pines

This past week I finished up the remaining point count routes, which included a route through coastal mixed forests along the extreme eastern edge of Frontenac Provincial Park. I accessed the habitat via a lengthy stretch of the Cataraqui Trail. Weather was perfect for surveying and it was fabulous to get and see this area of the park. Dominant species encountered during the morning were Yellow-rumped Warbler, Pine Warbler, Chipping Sparrow, Black-and-white Warbler and Red-eyed Vireo with a few “goodies” mixed in here and there.

Atop a ridge looking to Buck Lake

The survey route passed through a wide variety of habitats but the main target was mature mixed forest occurring along shorelines of large lakes in the area. Most lakes around here are steep in slope along the perimeter and lined with a high percentage of Eastern White Pine and Eastern White Cedar but I wanted a route that could be accessed relatively easily on foot.

Waterfall near Slide Lake

I was impressed with the high number of clear, gravel bottomed, moving streams in this area of the park. Since early June I’ve been logging locations of suitable stream habitat for breeding Louisiana Waterthrushes with the intention of returning in May, 2009 to inventory populations of this species in Frontenac Park. This particular stream was quite a torrent along its length, ending with a flourishing waterfall as it emptied into South Bay of Buck Lake.

Prairie Warbler habitat

The most significant finding of the morning was of a small colony of Prairie Warblers along the sloped and scrub-bearing banks of Slide Lake!

Prairie Warbler habitat

This is fairly typical habitat for this rare warbler in Ontario-rocky shorelines of lakes with a large component of successional scrub habitat.

I recorded this video with my ancient Canon A70 point and shoot camera to try and capture some audio of the singing males. A male flew into the small tree directly behind where I sat for a break at the end of the day and sang repeatedly at close range. I wish I’d had my HD camera as this particular male remained very close for about 10-20 minutes.

Click here for HD version (a little less than HD resolution due to use of digital zoom)

This two minute video was recorded yesterday afternoon at one of our field sites in Frontenac Provincial Park. I stumbled across this site on a point count route that spans predominantly young deciduous forest from the Trail Centre to Big Salmon Lake. The site is an unusual “island” of mature hardwoods surrounded by rock barren meadows and successional forest. Arriving at my point count station in the interior of this mature woodlot, I knew it was going to be a busy ten-minute survey as a dizzying variety of breeding birds were wheeling about in all directions. Scarlet Tanager, Yellow-throated Vireo, Ovenbird, Least Flycatcher and American Redstarts were the most conspicuous species noted. The male redstarts were particularly memorable, singing from everywhere and seemingly at all times. In this region of the Frontenac, American Redstarts are most numerous in wet deciduous woodland with a dense shrub understory and this site has it in spades.

I spent a good 3-4 hours at this site on a previous visit in search of nests for the purposes of gathering data on breeding demographics of regionally “common” landbird species. The American Redstart nest featured above took over an hour to locate as I followed the male on a proverbial “wild goose chase” to an array of curious locations throughout the forest without any success until I finally tracked down a female carrying food to a nest about 7m high in the main fork of a young maple. Males can be polygynous, often holding court with multiple nests, mates and territories within the same breeding season. This might explain why the male seemed to be leading me around through such a large area.

I revisited the nest on the following day, a rather wet and dreary afternoon, with the intention of filming the adults feeding young at the nest. The chicks were just a few days from fledging and were therefore demanding a lot of attention in the form of proteins and household maintenance. The chicks were no doubt getting restless with the cramped conditions as no less than four of them, nearly full grown, were packed into this little cup nest. The chicks frequently stretched and flapped their wings in the time I was there. Both male and female were appropriately attentive, visiting the nest equally as much, about 5 visits/hour per adult individual. Both sexes carried away fecal sacs from the young and the male seemed to bring a substantially larger total mass of food to the nestlings. It was hard to identify the offerings from a distance but it seemed as though moth caterpillars were the food of choice. I also noted that the female would brood the young during brief periods of the heaviest precipitation. The pair were fascinating to watch, particularly the male, who was an amazingly adept hunter of green larvae hiding in the foliage.

Common Nighthawk nest contents

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Although arguably the most studied nightjar in North America, the Common Nighthawk remains poorly known (Poulin et.al. 1996).

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Species Abstract
Common Nighthawk (Chordeiles minor)

Habitat=primarily nests in open habitats such as rock barrens (also gravel roofs in urban areas)
Area sensitive=?
Average clutch size=2
Nest building period=0 (no nest built)
Incubation period=19 days
Microhabitat=on ground on substrates of either rock, sand, gravel, lichens etc.
Egg colour=variable; creamy white to pale olive gray, heavily speckled with greys, browns and blacks.
Nest site selection=female
Incubation=primarily female
Parasitized by cowbirds=no
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This Common Nighthawk nest was first discovered at our Rock Ridge MAPS site on June 2, 2009. The female was inadvertently flushed from the nest when traversing one of the countless rocky flats at the site. Incidentally, a Whip-poor-will nest was also discovered on this day, less than 1km from the nighthawk nest. There won’t be many days of nest searching where that happens! Both of these species of the nightjar family have been much in the news of late because of their concurrent and precipitous decline in populations. Common Nighthawk was officially designated as a Species at Risk by COSEWIC in 2007 (Threatened) while Whip-poor-will was just recently recommended for listing in April of this year (Threatened). Nightjars are most active at dawn and dusk and are uniquely adapted to a food source of flying insects such as moths. It is suggested that the presence of a tapeta lucidum, a reflective structure of the choroid part of the eye, aids their vision during low light levels (Nicol and Arnott 1974). Relatively little is known about the breeding ecology and population dynamics of these two species, both of which commonly breed in the Frontenac Arch region of Ontario. Project Whip-poor-will will be starting up soon and will be designed to survey all nightjar populations in the FBS study area.

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The photo of the “nest” above is typical for Common Nighthawks where the eggs, usually two in a full clutch, are laid directly on the ground without any addition of materials or linings. They will sometime excavate a small scrape to contain the clutch but this activity seems to be determined by the habitat in which they choose to nest. The habitat for nesting nighthawks is quite variable, ranging from gravel rooftops in urban locations to a variety of open habitats adjacent to forests. They frequently inhabit rock barrens as in this particular case but will also nest in recently burned or clearcut forests as well as agricultural fields and grasslands throughout the continent.

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Male does not directly guard the nest (Dexter 1952) but may dive and boom over nest sites (Rust 1947); in addition, male may defend nest by wing-beating and hissing with mouth wide open (Dexter 1952). Female may use injury-feigning behaviour (fly away, then hiss at intruder) when flushed from eggs or young (Tomkins 1942).

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I spent no more than three minutes in the vicinity of the nest as I didn’t want to cause any excess amount of distress to the adult tending the eggs. I have a precise fix on its location and will be able to check on its progress at a distance from now on. The photos below provide a longer perspective on the nest site in terms of habitat. I have flushed several of both Common Nighthawk and Whip-poor-will in the area of our Rock Ridge MAPS station since the initial discovery of this nest but have not yet turned up any additional nest sites. The park has a large amount of suitable habitat for Common Nighthawks, perhaps about 1200 hectares worth, which suggests that the species might be common throughout rock barren areas. I will be traveling through much of the barrens starting next week for point count surveys and hope to encounter more of these fascinating birds.
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Nest site on rocky slope

nesting habitat

Forest floor of regenerating coniferous forest

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Returned to the Hemlock Lake site yesterday to begin searching for mistnet locations and to get a better picture of the breeding bird community for our study. The visit was considerably more comfortable than my last when black flies were particularly menacing! This latest visit was cool with very few biting insects, which afforded me a great opportunity to get to know the site a bit better. What a difference a couple of weeks can make in the late spring! The emerging foliage was substantially further along, which created a much different looking landscape. Site visits in winter and early spring gave me a solid understanding of the scale, topography and structure of the site but I knew that it wouldn’t be possible to even consider positoning net locations until the canopy and understory had matured.

Upon entry to the site, I heard Eastern Towhee, Scarlet Tanager, Nashville Warbler and a concert of voice-battling Ovenbirds. Further along to where the forest turns from deciduous to mixed-coniferous, I encountered Black-and-white, Magnolia, Black-throated Blue and Blackburnian Warblers, all species we were expecting at the site. Also of interest were at least two territories of Winter Wren, one of the most vocally adept species on the planet! I was able to record a few seconds of one of our talented males holding territory in the site along with one of the unavoidable male Ovenbirds (click play to listen).

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Evidence of active nesting by many species included alarm calls, adults carrying nesting material and territorial disputes. I didn’t find a great number of nests but I did mark locations where a nest was suspected. I will have to return in a few days to a week to confirm presumed nest sites of Ovenbird, Black-and-white Warbler and Eastern Towhee among others.

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However, I did manage to find the nest of a Brown Creeper, which was discovered by patiently watching movements and behaviour of a pair in the standing dead timber at the edge of Hemlock Lake.  After sitting quietly for about 45 minutes, I was finally rewarded with the observation of an adult entering a tree with nesting material. The Brown Creeper places its nest almost exclusively in dead trees, between a loose flap of bark and the trunk. They build a hammock shaped nest of sticks and fibres, which is secured to the bark with insect-egg casings and spider silk. The nest will now be monitored with the goal of deriving a nest outcome. The information will be important to our demographic studies of breeding birds in the FBS study area and will be submitted to the Ontario Nest Records Scheme and Project Nestwatch for province-wide monitoring efforts. A closer view of the nest site is provided below.

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Brown Creeper nest site

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The most exciting discovery of the day led to this short video of a waterthrush carrying material to a nest in roots of an upturned tree along a clear moving stream. Northern Waterthrushes were quite vocal in the vicinity but this particular pair were all but silent except for some occassional contact calls between male and female. The calls were diagnostic of Louisiana Waterthrush but I will have to confirm identify of the nest owners at a later date. Northern Waterthrush are very similar in appearance with some subtle differences. It is best to distinguish the two by song, which are distinct. The Louisiana Waterthrush is a Species At Risk and a specialty of the Frontenac Arch region where an abundance of mature forest and clear moving streams provide suitable nesting habitat. The video is of less than ideal quality but one can clearly see an adult entering the roots about halfway up the screen to the left of the small tree trunk. The bird is more clearly seen at the end of the clip as it cryptically runs through the stream and out of the frame. Click here for HD version of this video clip.

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The Hemlock Lake MAPS station will begin operating in early June and continue with one visit per ten-day block through the final visit in late July. We will also be conducting a standardized nest monitoring study at this and the other two MAPS stations in the FBS study area. The site is turning out to be a terrific find and hopefully a long-term home for our research and monitoring programs.

Notable Species at Hemlock Lake (May 18,2009)

Great Blue Heron
Red-shouldered Hawk
Eastern Kingbird
Brown Creeper
Winter Wren
Wood Thrush
Swainson’s Thrush (migrant)
Northern Parula (migrant)
Nashville Warbler
Yellow Warbler
Chestnut-sided Warbler
Magnolia Warbler
Cerulean Warbler
Black-throated Blue Warbler
Black-throated Green Warbler
Blackburnian Warbler
Black-and-white Warbler
Ovenbird
Northern Waterthrush
Louisiana Waterthrush
Common Yellowthroat
Scarlet Tanager
Eastern Towhee
Field Sparrow
Song Sparrow
White-throated Sparrow
Rose-breasted Grosbeak
Baltimore Oriole