In search of the elusive Newfoundland Gray-cheeked Thrush: Part I


The crew met in Corner Brook, at the Grenfell campus of Memorial University of Newfoundland (MUN), in the lab of our collaborator Dr. Ian Warkentin, who is supporting the project but not joining us in the field. We are gathering data for the dissertation project of Alyssa FitzGerald, a student at SUNY Albany, where she works under the curator of birds at the New York State Museum, Dr. Jeremy Kirchman. Our goal: Find and capture one of the most elusive species in Newfoundland, the Gray-cheeked Thrush (Catharus minimus), to collect blood samples so as to determine whether the island populations are genetically distinct from those on the mainland. Jeremy will be with us until the 19th of June, after which the remainder of our crew will continue on for an additional four weeks. The crew is rounded out by Rinchen Boardman, a master bird bander from the Thunder Cape Bird Observatory in Ontario, and Lucy Welsh, who recently earned a BS in Biology and worked with Wood Thrushes (Hylocichla mustelina) in Belize and Pennsylvania.

Planning our expedition to Swale Island, Terra Nova National Park.

Planning our expedition to Swale Island, Terra Nova National Park.

Collectively, we have a ton of relevant field knowledge and experience, and everyone is enthusiastic about the task ahead of us, which includes fieldwork throughout Newfoundland followed by an expedition to the remote province of Labrador.

We assembled our gear, picked up our rental vehicles, and purchased groceries for the first week of camp. A few hours later we arrived at our first field site, along Burgeo Road in the southwestern portion of the island, where the ornithologist Joe. T. Marshall camped in the early 1980s to survey for Gray-cheeked Thrushes, and where more recently a Canadian biologist, Peter Thomas, captured some of these elusive birds for genetic samples that will be used in our study. It was quite cold (with on and off rain) when we pitched camp, but the crew was eager to enter the field and begin work despite the difficult weather. For the first few days, we got into the routine of rising before dawn, sliding into our long underwear and wellies (rubber boots), DSC03913and hopping around trying to stay warm in near freezing weather as we systematically surveyed for birds at points along the road, each separated by 250 meters so as to avoid counting the same birds twice. We worked together to standardize our methods, and to make sure that everyone could identify the various bird sounds and tree species that we encountered. Not far from Burnt Pond, where Marshall had detected Gray-cheeks more than 30 years ago, we had our first detection and capture (via mist nets that we set up after the survey) – a second-year male that we banded and bled before releasing it.

A second-year Newfoundland Gray-cheeked Thrush (C. m. minimus); notice the how the yellow on the lower mandible extends beyond the nostrils, a unique feature of this subspecies.

A second-year Newfoundland Gray-cheeked Thrush (C. m. minimus); notice the how the yellow on the lower mandible extends beyond the nostrils, a unique feature of this subspecies.

Although I have collected blood from many Veeries (Catharus fuscescens), the closest relative of the Gray-cheeked Thrush, during my master’s research on the former species’ mating system in Delaware, this was the first time that I had the opportunity to bleed a Gray-cheek. The bird was beautiful and very cooperative, and I couldn’t help but feel some pride as I held the bird in my hand. We are literally following in the footsteps of Marshall, who cared so much for these birds and just passed away in February of this year. He would have been proud.

On 11 Jun, the crew split up to cover more ground. Alyssa and Lucy continued south to the town of Burgeo, where they were apparently unsuccessful finding Gray-cheeks (as per a message received a couple days ago). I traveled to eastern Newfoundland with Jeremy and Rinchen, to Terra Nova National Park, where we surveyed points along the road to Salvage and Ochre Hill. The populations in the east are very low density, and unfortunately (as we discovered) do not respond well to playback of their songs (i.e., via a speaker system that we use to lure them into nets). In fact, we have not heard them sing at all, but only give occasional ‘peer’ calls which they intersperse with a strange two-toned call that differs slightly from those described by Marshall in that it continues upward in frequency without dropping at the end.

Habitat on Ochre Hill, where spongy white lichen line the trails, winding through bogs with stunted stands of Black Spruce and Balsam Fir

Habitat on Ochre Hill, where spongy white lichen line the trails, winding through bogs with stunted stands of Black Spruce and Balsam Fir

When I first heard the sound, I suspected that the peculiar call was made by a Catharus thrush because it is very similar to one made by its tropical cousin with whom I am acquainted, the Slaty-backed Nightingale Thrush (Catharus fuscater); but it wasn’t until the following day that I was able to confirm that this odd sound actually came from our target species (but see following post). On Ochre Hill, I left the trail and waded through an Alder thicket, tracking the bird for about 100m through the dense fog and drizzle, before I finally got my chance to see and record the bird with my microphone. I was soaked from the wet vegetation and swamp, but exhilarated to find the bird and confirm the species’ presence in the park. Ever since, we have used this strange call to identify Gray-cheeks at Terra Nova from a distance, because they seem to use it more frequently than (and sometimes in conjunction with) the ‘peer’ call that most people are familiar with. It is just another example of how little we know about these birds’ lives and behavior. Even so, we have been unable to capture the Gray-cheeks in Terra Nova because they do not respond to playback; indeed, we have yet to hear a single song, even though we have heard them calling in the early morning and late dusk hours when we would normally expect to hear them singing. [NOTE: this turned out to be a mis-identification when more recordings were examined; see following post.]

DSC03888On the morning of 15 Jun, we traveled by boat to Swale Island, uninhabited by man, to search for Gray-cheeks and conduct the very first ornithological surveys of the island. The rangers confirmed that no systematic surveys have been conducted of the avifauna of Swale, so it was a treat to be the first ornithologists to do so, the only place in North America for which I have had that privelege. We found Hermit Thrushes (Catharus guttatus) on the island and an additional 11 bird species, but alas, no Gray-cheeks. DSC03896After we finished our surveys (including some quantification of the vegetation community there), our friendly park ranger guide Tyrone transported us to a remote field cabin at Park Harbour, another section of the park seldom visited by anyone but the rangers themselves (“like they would!”). We spent an evening and the following morning surveying the surrounding forests and bogs.

At dusk, we hiked up a valley behind the cabin in search of Gray-cheeks. There were several Hermit Thrushes singing, and we were beginning to get discouraged because it was nearly dark (around 10:00 PM), when suddenly we heard in the distance the strange two-toned call that I had recorded the preceding days on the mainland. This was followed by a loud (long-distance) “PEER!” and a second bird responded from the other side of the valley with a softer version of the same call. As I have often heard the Veeries do, the two birds modulated the volume of their calls and ‘rendezvoused’ in the middle of the valley in the darkness before falling silent.

Boreal Chickadee (Peocile hudsonicus) in the hand.

Boreal Chickadee (Peocile hudsonicus) in the hand.

Thus, there were Gray-cheeks in the valley, but like the rest of the locations we surveyed in Terra Nova, there are apparently very few of them. We set up our net with the hope of returning the next morning before dawn to try the playback, but our effort was in vain; the birds did not respond to the playback, nor did we hear a single song. Unfortunately, its cryptic behavior and lack of singing makes the species incredibly difficult to detect in Terra Nova, and because of this, their presence (apparently in very low population density) may have gone unnoticed in recent surveys. Nevertheless, our spirits are high, and we will not give up! More updates to come when next I find an internet connection, which may be awhile.

(This just in: On 16 Jun, we received word from Alyssa and Lucy, who kayaked to an island off the shore of Burgeo and captured three more Gray-cheeks there!). The adventure continues…

DSC03886

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Categories: Exploration, Natural History, Ornithology

2 comments

  1. Perhaps one should become familiar with the Gray Cheeked Thrush before going into the field. There is a distinct difference between a Hermit Thrush’s song and that of a Gray Cheeked Thrush – this seems rather basic. Today I listened to and observed a Gray Cheeked Thrush in La Manche. This region should be included in your study. Here it is : https://www.flickr.com/photos/beothic/19173095410/in/dateposted/
    Cheers,John

    • Hey John, thanks for commenting. You are right, the songs of these species are quite different and easy to distinguish. The Hermit vocalization that I mistook for a Gray-cheek was a call (not song!), one that Marshall (2000) called the “sour note,” and the two are pretty similar structurally. The call repertoires of these species (and all Catharus!) are poorly studied and can be highly variable. Thanks for the link to your pic! The leader of our crew, Alyssa FitzGerald, surveyed in La Manche last season and caught a few birds from there for the study! Best, Matthew

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