Sunday, September 25, 2016

Identification of a South Polar Skua

Skuas in the Maritimes

Most Great Skua reports in our province are of birds between August and early April (McLaren 2012), while some birds can remain in the North Atlantic throughout the year (Newell et al. 2013). Great Skuas have been recorded in summer off New England and the Maritimes (Dunne 2006). The South Polar Skua is typically seen from late May through September (Mclaren 2012). Given the timing overlap, care must be taken when identifying these birds.

Size
Those with experience seeing both skua species notice subtle differences in size and structure between the two species expected in Nova Scotia waters. In relation to Great, South Polar averages smaller and more lightly built, with more slender bill and narrow wings (Alderfer 2014). Newell et al. (2013) caution that these differences are difficult to quantify, and due to the overlap in bill, wing, and tarsus measurements, species identification usually relies on plumage features.

Adult Plumage
Adult South Polar Skuas are cold-toned, with generally plain head, neck and upperparts, except for pale buff and gold streaks on the hindneck (Newell et al. 2013). Adult Greats are warm-toned, with extensive pale buff and gold streaking and mottling on the head, neck and upperparts (Newell et al. 2013). Most, but not all, adults show a dark cap (Dunne 2006). Both of these species have light, intermediate and dark morphs, but McLaren (2012) states that the light morph South Polar is extremely rare in the North Atlantic. Behrens and Cox (2013) describe how Great Skuas typically show clear contrast between the paler wing coverts and darker flight feathers and very little contrast between the coverts and back, whereas South Polar Skuas have uniformly blackish wings.

Juvenile Plumage
Juvenile South Polar Skuas fledge in about February, and have medium to dark grey head and body plumage contrasting with dark upperparts and underwing coverts. They sometimes show a paler back and can have a slightly paler band across the nape or distinctly paler head than body (Behrens and Cox 2013). Juvenile Great Skuas fledge in about August, have variably rufous (or reddish)-toned underparts, a dark hood and contrasting dark upperparts, with broad, paler, crescent-shaped subterminal markings on the scapulars and wing coverts (Newell et al. 2013). They are overall darker and cleaner looking than adults and show two-toned wings similar to adults, but with less contrast (Behrens and Cox 2013). The leading edge of the wing is often rusty brown (Behrens and Cox 2013). Some dark juvenile Great Skuas can appear to entirely lack the pale marks on the scapulars and thus are similar to South Polar. (Newell et al. 2013)


The September Brier Pelagic Skua

On September 24, 2016, forty-one birders gathered at Brier Island to partake in a pelagic trip organized by Mark Dennis. Two skuas were observed during the 4.5 hours that we were in the Bay of Fundy. Views of the second skua prompted discussion on the boat as to its identification. Many photos were taken and it was decided that we should review the literature and photographs later to reach a confident conclusion at the species level. My photos of this bird are presented here.

Figure 1. South Polar Skua in the Bay of Fundy on Sep 24, 2016. Shape and size are hard to judge, but the head appears small, the bill slightly thinner and chest less bulging in comparison to a Great Skua. The dark portion of the face appears to form a mask rather than a cap like in Great Skua. Photo by Alix d'Entremont.

Figure 2. South Polar Skua in the Bay of Fundy on Sep 24, 2016. The pale nape is evident here, but otherwise, the upperparts are uniform dark without any appreciable mottling or streaking. Photo by Alix d'Entremont.

Figure 3. South Polar Skua in the Bay of Fundy on Sep 24, 2016. The almost complete primary moult is visible in this photo. The outer two primaries (P9 and P10) are growing. Photo by Alix d'Entremont.

Since primary moult is visible on this bird, a recent paper titled South Polar and Great Skuas: the timing of primary moult as an aid to identification (Newell et al. 2013) provides helpful details. This work presents a moult scoring system and an accompanying graph where date and moult score are the x and y axis, respectively. A moult score of 0 points represents a bird with old and unmoulted primaries, while 50 points would be given to a bird with recently and completely moulted primaries.

Our September 24 skua has almost completed moulting its primary feathers. P1-P8 are completely grown (40 pts) while P9 is almost (4 pts) and P10 is more than half grown (3 pts). This gives our bird a primary moult score of 47; this combined with the date of September 24, plots this bird in a region of the moult score graph presented in Newell et al. (2013) that is unique to older South Polar Skuas. The authors also urge that the resulting identification from the moult score graph should align with other features of the bird in question. The uniform back and wing-coverts and pale neck are supportive of South Polar Skua.

The moult score graph in Newell et al. (2013) is a very useful tool to confirm tentative skua identifications. We were fortunate that the age and moult timing of this bird resulted in only one option (adult or sub-adult South Polar Skua). Using the graph with some individuals will result in two or three options. In those cases, aging, morphology and plumage features are required to narrow down to species.


References

Alderfer, J., J.L. Dunn. 2014. (Ed). Complete Birds of North America, 2nd Edition. National Geographic Society. Washington DC, USA.

Dunne, P. 2006. Pete Dunne's Essential Field Guide Companion: A Comprehensive Resource for Identifying North American Birds. Houghton Mifflin Company, New York, NY.

McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada

Newell, D., S.N.G. Howell and D. Lopez-Velasco. 2013. South Polar and Great Skuas: the timing of primary moult as an aid to identification. British Birds Issue 106, pp. 325-346.

Behrens, K and C. Cox. 2013. Peterson Reference Guide to Seawatching: Eastern Waterbirds in Flight. Houghton Mifflin Harcourt Publishing Company, New York, NY.

Sunday, September 11, 2016

Cerulean Warbler on Bon Portage

Hatch-year female Cerulean Warbler at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Status & Recent Sightings
McLaren (2012) rates the Cerulean Warbler as a rare vagrant to Nova Scotia with about 45 reported as of the end of 2010. The first was found on Sable Island on June 6, 1968 by C. Bell (Nova Scotia Birds Society Newsletter Vol. 10 No. 2). Sightings since 2010 are listed below:

Aug. 17, 2011 - Bon Portage Island - Lucas Berrigan
Oct. 2, 2011 - Chebucto Head, Halifax - David Currie (ph.)
Oct. 2, 2011 - Hartlen Point, Halifax - Dennis Garratt, fide David Currie (3 BIRDS!)
May 18, 2012 - Halifax Public Gardens - Dennis Garratt (female)
Sep. 2014 - Lower Sackville, Halifax - Don Robar (fide Clarence Stevens, no details)
Sep. 3, 2016 - Bon Portage Island - David Bell & Alix d'Entremont (imm. female, ph.)
Sep. 2016 - Pleasant Hill Cemetery, Halifax - Dennis Garratt (imm. female)

*The Oct. 2012 Ceruleans above were part of a larger fallout due to a low-pressure system that moved up the U.S. coast towards us. This system propelled migrants offshore and then directly to Nova Scotia. (NS Birds Vol. 54 No. 1)

Field Encounter
Chloe, Molly and Ben Symons joined me on a Zodiac trip to Bon Portage on September 3, 2016. I brought them to the island to show them the bird banding done by the Atlantic Bird Observatory staff.

We watched a few birds get processed and then made our way south towards the lighthouse. I pulled out an immature Leach's Storm Petrel from a burrow to show the group. While observing the few shorebirds in the pond near the lighthouse, a bat flew in and landed on one of the buildings. I was able to get a few photos and Andrew Hebda (Curator of Zoology at the Nova Scotia Museum) as well as Hugh Broders (Professor of Biology at Saint Mary's University) believe it is likely a Silver-haired Bat.

Silver-haired Bat at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Silver-haired Bat at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Silver-haired Bat at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Silver-haired Bat at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

We then made our way back to the cabins near the wharf. The area around the cabins is often one of the busiest places for passerines on the island. Chloe and I observed a warbler that I first took as a Bay-breasted, but wasn't quite sure so I pulled out the camera and snapped a few photos. Bay-breasteds don't have a pale supercillium, so it wasn't quite right for that species.

Hatch-year female Cerulean Warbler at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Hatch-year female Cerulean Warbler at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

I asked David Bell (bander-in-charge) to check my photos and he was glad to share that he thought it was a Cerulean Warbler. David soon re-found the birth north of the wharf while walking to check the mist nets. David had actually briefly seen the Cerulean earlier in the day, but the brief views weren't enough to confirm its ID. I had never seen a Cerulean Warbler and wasn't quite ready for such a pale coloured and blandly patterned bird. Had it been an adult male, I'd have known right away. The lack of blue tones or streaking above along with the extensive yellow below make it a hatch-year female.

Below are a few photos of a hatch-year Yellow-bellied Flycatcher that I took after the banding and processing was complete.

Hatch-year Yellow-bellied Flycatcher at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Hatch-year Yellow-bellied Flycatcher at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

Hatch-year Yellow-bellied Flycatcher at Bon Portage, Shelburne County, September 3, 2016. Photo by Alix d'Entremont.

References:
McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada

Thursday, August 18, 2016

Pubnico Pelagic 2016

The yearly Pubnico Pelagic occured on August 13, 2016 this year. See Pubnico Pelagic 2014 and Pubnico Pelagic 2015 for the previous two years' blog posts. I also create a YouTube video for each trip, the 2016 video can be seen below, or follow this link Pubnico Pelagic 2016.



This trip is cause for excitement many months before we actually leave the wharf. It is a chance for those of us who rarely go offshore to get close-up views of many species that are only specs on the horizon when viewed from land. This year I had already seen both species of storm-petrel, a Pomarine Jaeger (eBird Checklist) and the four expected species of shearwater (eBird Checklist) on previous trips. This meant that most species that we would see wouldn't be new ticks for the year for me.

Cory's Shearwater (borealis subspecies) at German Bank, August 13, 2016. Photo by Alix d'Entremont.

An Audubon's Shearwater was photographed near Grand Manan on August 11, 2016, and a South Polar Skua was observed on a Brier Island whale trip on August 12, 2016. These two sightings combined with the very warm sea surface temperature maps (20 degrees Celcius just west of NS) seemed to suggest that we had the chance of finding something big.

Ronnie d'Entremont organized the trip again this year and Steven d'Entremont captained the Rebecca Lynn I. The boat left at about 5:30 am from Dennis Point Wharf in Lower West Pubnico. Below is a list of the participants:

Ronnie d'Entremont
Raymond d'Entremont
Paul Gould
Eric Mills
Bruce Stevens
Alan Covert
Ken McKenna
Kevin Lantz
Larry Neily
Mark Dennis
Mike MacDonald
Jane Alexander
Keith Lowe
Reinhard Geisler
Lori Mathis
Jerry Mathis
Graham Williams
Peter Brannon
Diane LeBlanc
Liz Voellinger
Simon d'Entremont
Alix d'Entremont
Peggy Scanlan
Chris Pepper
Angela Granchelli

Some of the crew; left to right: Mark Dennis, Ken McKenna, Liz Voellinger, Chris Pepper, Eric Mills, ?? and Raymond d'Entremont. Photo by Alix d'Entremont.

The first interesting observation of the trip were of shearwaters in Lobster Bay, before we even reached the Mud Islands. The Bon Portage crew regularly get good numbers of shearwaters passing by the island, so seeing them in Lobster Bay isn't really unexpected.

We took the opportunity to sail near to Round Island on our way out to sea. Bruce Stevens spotted a Black-crowned Night-Heron as it flew over the island. I am almost convinced that these rare Nova Scotia breeders are nesting on nearby Mud Island. I had one on Round Island in 2012 (eBird) and another three earlier this year (eBird). It has or currently does nest on Seal Island and islands near Cape Sable Island (McLaren 2012). Breeding of this species has been confirmed again this year on Bon Portage Island (eBird), where it has been breeding since 1977 (McLaren 2012).

Once we passed the Mud Islands, a few of us thought we saw a few Manx, but they were too distant to be sure of the identification. A Cory's was also likely seen fairly early, but it too was gone before anyone else got to see it.

We often hear of migrant birds landing on boats that can be many miles offshore. On this trip, we had three species of Passerine that were sighted quite far from land: Barn Swallow, Yellow Warbler and Brown-headed Cowbird. The cowbird flew 3 or 4 circles around the boat as two dozen birders watched it. We assumed it would try to land, but it flew off and returned later to circle the boat again without landing.

Brown-headed Cowbird, hatch-year Barn Swallow and Yellow Warbler, August 13, 2016. Photos by Alix d'Entremont.

My first ever Lesser Black-backed Gull was one seen on the Pubnico Pelagic in 2012. That first bird was an adult while the one seen during this 2016 trip looked like an second-cycle type bird with still juvenile looking inner primaries. It appears to be finishing its second prebasic moult as it is growing the outer primaries and inner secondaries.

Lesser Black-backed Gull at German Bank, August 13, 2016. Photo by Alix d'Entremont.

I spotted the only Northern Fulmar during the entire trip when it was a little distance away. It did fly in a bit closer, but only gave us one chance for photos. The Great Shearwaters outnumbered the Sooty Shearwaters with a ratio of ??.

Northern Fulmar at German Bank, August 13, 2016Photo by Alix d'Entremont.

Sooty Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

Great Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

At first, the only storm-petrels that we had were Wilson's, but finally, Mark Dennis yelled out Leach's and we got some great views of both species to compare size, markings and flight style. Ronnie commented that photographing these tiny pelagic birds is similar in difficulty to "trying to eat jello with chopsticks". I agree.

Wilson's Storm-Petrel pitter-pattering on the water's surface at German Bank, August 13, 2016Photo by Alix d'Entremont

Leach's Storm-Petrel at German Bank, August 13, 2016Photo by Alix d'Entremont

The two other expected species of shearwater obligingly showed themselves. The first was a Cory's Shearwater (Calonectris diomedia) spotted by Dr. Eric Mills that gave us adequate underside views to eliminate the C.d. diomedia (Scopoli's) which has yet to be photographically confirmed in Nova Scotia. See the first photo in this blog post for an underside view of this Cory's. A sight record of Scopoli's exists from Sable Island in September 2015 (eBird Checklist) and Mills et al. (2015) summarise the issue in an issue of NS Birds. The British and Dutch authorities have separated the two as distinct species, Calonectris diomedia (Scopoli's) and Calonectris borealis (Cory's), but in North America, they remain as subspecies.

Cory's Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

Rounding off the four expected shearwater species was an extremely confiding Manx Shearwater. These small shearwaters typically only give brief views, and from my experience, aren't attracted to chum as much as the others. This Manx came in to the chum, at one point sitting on the water less than 10 feet from us. We watched as it circled the boat and dove completely in the water for a number of seconds. It was diving underwater when the other larger birds like Herring Gulls would fly in to steal the fish pieces that the Manx was trying to catch - a great technique for evading the bullies.

Manx Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

Manx Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

Manx Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

Manx Shearwater at German Bank, August 13, 2016Photo by Alix d'Entremont.

I thought I had 3 Black-legged Kittiwake recently from Outer Bald Island, but they were a few kilometres away, so I couldn't really rule out Bonaparte's or other small gulls, so didn't add them to my eBird checklist. I needed the species for my year list, so the adult that gave a good show was my first of the year.

Adult Black-legged Kittiwake at German Bank, August 13, 2016Photo by Alix d'Entremont.

A Northern Gannet came in for some chum so we got good fews of hooks with lead weights that were caught in its webbing. It also seemed to have an issue with one of its wings. After having observed the quick and agile Manx Shearwater, this gannet appeared gangly and uncoordinated as it went for the pieces of fish just below the water's surface.

Adult Northern Gannet at German Bank, August 13, 2016Photo by Alix d'Entremont.

Northern Gannet with line, hooks and lead weights caught in its webbing at German Bank, August 13, 2016Photo by Alix d'Entremont.

eBird Checklists:

Leg 1 (5:30-6:30)
Leg 2 (6:30-7:30)
Leg 3 (7:30-8:30)
Leg 4 (8:30-9:30)
Leg 5 (9:30-10:30)
Leg 6 (10:30-11:30)
Leg 7 (11:30-12:30)
Leg 8 (12:30-13:30)
Leg 9 (13:30-14:30)
Leg 10 (14:30-15:30)

Below is a list of all species and total count during all legs of the trip.

Species Name / Species Count
American Black Duck 1
Common Eider 49
Northern Fulmar 1
Cory's Shearwater 2
Great Shearwater 544
Sooty Shearwater 28
Manx Shearwater 1
shearwater sp. 2
Wilson's Storm-Petrel 20
Leach's Storm-Petrel 3
storm-petrel sp. 2
Northern Gannet 65
Great Cormorant 1
Double-crested Cormorant 112
Great Blue Heron 2
Black-crowned Night-Heron 1
Bald Eagle 2
Black-bellied Plover 8
Ruddy Turnstone 4
Least Sandpiper 17
White-rumped Sandpiper 3
Semipalmated Sandpiper 7
peep sp. 31
Short-billed Dowitcher 2
Red-necked Phalarope 79
Red Phalarope 400
Red-necked/Red Phalarope 416
Pomarine Jaeger 1
Razorbill 2
Black Guillemot 275
Atlantic Puffin 110
alcid sp. 2
Black-legged Kittiwake 2
Herring Gull 410
Lesser Black-backed Gull 3
Great Black-backed Gull 280
Common Tern 8
Arctic Tern 2
Common/Arctic Tern 21
American Crow 4
Common Raven 9
Barn Swallow 2
swallow sp. 3
Yellow Warbler 1
Brown-headed Cowbird 1
passerine sp. 1

The hopes of a "mega", a very rare bird, did not materialise. The sea surface temperature as measured by our boats instruments was only about 13 degrees Celcius, much cooler than what was displayed on Rutger's SST maps. It was a very pleasant trip in terms of sea conditions and weather and it was a pleasure to get to see birders that I rarely bump into. I'm looking forward to next year's trip.

References
McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada.

Mills, Eric L., Bruce Stevens & Jim Wilson. 2015. Cory's and Scopoli's Shearwaters - a Challenge for Atlantic Canadian Birders. NS Birds Vol. 57, No. 4. pp. 38-43.

Saturday, August 6, 2016

Breeding Leach's Storm-Petrels in Southwest Nova Scotia

Leach's Storm-Petrels in Nova Scotia
Leach's Storm-Petrels are a species frequently seen by fisherman, but only seen by birders who put the effort in. While they do nest on many of our Atlantic Coast islands, they usually feed far offshore and only travel to and from their colonies at night (McLaren 2012). Going out to sea is the best way to see these birds, but you might catch a distant view of one from our headlands where they are only numerous during storm events. I observed a single individual in Yarmouth Harbour only a few hundred metres from the mainland on June 11, 2016, and two were seen at the same location a few days later by Ellis d'Entremont, so near shore sightings are a definite possibility but are rare.

Leach's Storm-Petrel at German Bank, August 29, 2015. Photo by Alix d'Entremont.

Bon Portage Island [43.469349, -65.751828] in Shelburne County is the most well known breeding site for Leach's Storm-Petrels in Nova Scotia, and is the largest in the Maritime Provinces (Stewart et al. 2015). An estimated 50,000 pairs (Oxley 1999) of these procellariiformes (tubenoses) spend the summer months on this island that is owned by Acadia University. The 3 km by 0.5 km mostly forested island, officially known as Outer Island on the maps, is internationally recognized as an Important Bird Area. Since fall of 1995, the Atlantic Bird Observatory monitors migration through mist netting.

During one of my first visits to Bon Portage, I met with Ingrid Pollet, a storm-petrel researcher. She has contributed to published studies such as Foraging movements of Leach's storm-petrels Oceanodroma leucorhoa during incubation where archival light loggers were used to show that the average foraging trips for adult Leach's Storm-Petrels on Bon Portage was 1303 km with an average trip time of about 5 to 6 days.

Banders' building on Bon Portage, September 2, 2012. Photo by Alix d'Entremont.

Weighing a Cape May Warbler on Bon Portage, September 2, 2012. Photo by Alix d'Entremont.

David Bell holding a Blackpoll Warbler with a radio transmitter on Bon Portage, August 23, 2014. Photo by Alix d'Entremont.

One of the field crew bunk houses on Bon Portage, September 2, 2012. Photo by Alix d'Entremont.

Ingrid Pollet reaching into a Leach's Storm-Petrel burrow for research on Bon Portage, July 21, 2013. Photo by Alix d'Entremont.

Ingrid Pollet holding an adult Leach's Storm-Petrel on Bon Portage, July 21, 2013. Photo by Alix d'Entremont

Ingrid Pollet holding a banded Leach's Storm-Petrel on Bon Portage, July 21, 2013. Photo by Alix d'Entremont.

The other important breeding site is a relatively smaller colony at Country Island, Guysborough County [45.101784, -61.542582]. This is a circular island at about 500 m in diameter with an estimated 8700 (Pollet et al. 2014a) to 12,000 (Env. Canada data) breeding pairs of Leach's Storm-Petrels.

While breeding popultion is difficult to monitor due to the remoteness of the colonies, the bird's nocturnal behaviour and its hidden burrow entrances, observations at Bon Portage and Country Island suggest that the population is stable or has declined slightly between the 1st and 2nd Maritime Breeding Bird Atlas. (Stewart et al. 2015)

The map below shows that Leach's Storm-Petrels are absent in the Bay of Fundy and the Northumberland Strait areas. This is due to their preference for the cooler Atlantic Coast waters and their requirement for predator free islands, which are much more common on our province's southern coast. Interestingly, Tufts (1986) describes a small colony near Louisburg found in 1954 that was on a mainland peninsula.

This Google Earth map is a fairly accurate depiction of all past and current Leach's Storm-Petrel colonies in Nova Scotia. The data comes from Environment Canada and the Maritime Breeding Bird Atlas projects.

July 2016 Environment Canada Surveys
During July 2016, I was contracted to do alcid and storm-petrel surveys for Environment Canada. The first half of July was fairly windy and my outboard motor was in for repairs for the better part of a week. This left me with little time to get to all of the islands that I had planned on visiting.

Ram Island [43.683657, -65.029942]
Ram Island is about 800 m by 300 m, has no trees, and is 6.5 km east of Lockeport. I visited this grassy island twice this summer, once on June 25, 2016 (eBird Checklist) and again on July 30, 2016 (eBird Checklist). During the first trip I concentrated on getting accurate numbers of Razorbills (8), Atlantic Puffins (28) and Black Guillemots (73).

Atlantic Puffin on Ram Island, Shelburne County, June 25, 2016. Photo by Alix d'Entremont.

A view of Ram Island from the eastern tip looking west on July 30, 2016. Photo by Bertin d'Eon. 

Environment Canada staff had provided me with historical information that showed that in 1976 they had found 25 pairs. Breeding was not confirmed at this site during the 1986-1990 (1st) or the 2006-2010 (2nd) Maritimes Breeding Bird Atlas. It is possible that this site hadn't been checked since 1976.

During the second trip on July 30, Bertin d'Eon and I concentrated on finding storm-petrel burrows. I found a hole on the side of a small grassy hill [43.682373, -65.027917] refered to as 'Site 1' on the map below. I played Leach's calls from my Sibley's app on my phone and immediately heard a response from the burrow. Two more burrows were found at this location, one of which I felt the adult inside the burrow while no breeding was confirmed for the other. Another nearby location labeled as 'Site 2' [43.682128, -65.028361] had two potential burrows, but to breeding was confirmed since there was no response to audio and the end of the holes were not reached.

This Google Earth map shows the two locations on Ram Island, Shelburne County, where Leach's Storm-Petrel burrows were located on July 30, 2016. Breeding was only confirmed at 'Site 1'.

'Site 1' where breeding was confirmed by a response from a bird in a burrow on Ram Island, Shelburne County, on July 30, 2016. Photo by Alix d'Entremont.

A Leach's Storm-Petrel burrow at 'Site 1' on Ram Island, Shelburne County, on July 30, 2016. Photo by Alix d'Entremont.


Mud Island [43.484239, -65.988819]
Known by locals as "The Mud", this mostly forested Yarmouth County island lies 21.5 km southwest of Pubnico and is 2.7 km by 1 km at its widest. It has long been known that Mud Island was used by hundreds of pairs of Leach's Storm-Petrels. I was lucky enough to make two trips out to the island, on July 12, 2016 (eBird Checklist) and again on July 27, 2016 (eBird Checklist).

The northwestern cobble beach on Mud Island, Yarmouth County, July 13, 2016. Photo by Alix d'Entremont.

The western shore of Mud Island, Yarmouth County, July 13, 2016. Photo by Alix d'Entremont.

The results of both trips were cause for concern. No active nests were found and most nests had been dug up and the adults killed. The damage extended through the entire forested area, but the very middle was not checked. Three clues to the identification of the predator are that no tracks or droppings were found; no storm-petrel flesh or bone was present, only many feathers; and corvid feathers seemed to be a common sight near the areas of destruction. Photos of the ruined burrows have been sent around to Environment Canada and Department of Natural Resources, but no concensus has been reached. I've been told by fishermen that mink could make it to the island by hitching a ride on a loaded lobster boat on dumping day, but some feel that crows or ravens are more likely.

Leach's Storm-Petrel burrow destruction on Mud Island, Yarmouth County, July 13, 2016. Photo by Alix d'Entremont.

Leach's Storm-Petrel burrow destruction on Mud Island, Yarmouth County, July 27, 2016. Photo by Alix d'Entremont.

Leach's Storm-Petrel burrow destruction on Mud Island, Yarmouth County, July 27, 2016. Photo by Alix d'Entremont.

Leach's Storm-Petrel burrow destruction on Mud Island, Yarmouth County, July 27, 2016. Photo by Alix d'Entremont.

Stoddart Island [43.471700, -65.712889]
This forested island is about 1.75 km south of Shag Harbour, Shelburne County, and is approximately 1 km by 1.3 km in size. Bertin d'Eon and I visited the island on July 21, 2016 (eBird Checklist) and were unable to find any burrows. All burrows on the island seemed to be used by meadow voles since the entrances were smaller than those on Bon Portage and each entrance had the droppings of a small mammal. Three meadow voles were briefly seen as they scurried from one hole to the next. The Environment Canada data on Stoddart Island simply stated that Leach's Storm-Petrels were present in 2006, but gave no estimation of colony size. The island could have been abandoned by the birds if a predator made it to its shores.

Outer Bald Island [43.599588, -66.023979]
The Outer Bald Island is a grassy island about 9 km south of Comeaus Hill and is owned by the Nova Scotia Nature Trust. A trip there on July 31, 2016 (eBird Checklist), by Alec d'Entremont, Florian Schmitt, Bertin d'Eon and myself was very successful.

Eighty-one (81) burrows found, most on the northern side [43.600406, -66.024145] of the island and the remainder on the north-western corner [43.600380, -66.024782]. Most burrows were too long to reach the end with your hand.

15 burrows where the end was reached, but nothing was found.
52 burrows where the end was not reached and nothing was found.
1 burrow with 1 adult & 1 egg
1 burrow with 1 adult
1 burrow with 1 chick
2 burrows with single hatched egg
1 burrow with a bad egg.
8 burrows were less than 30 cm long.
A few (~5 burrows had two entrances)

This Google Earth map shows Outer Bald Island. The Leach's Storm-Petrel burrows were found on the northern side and northwestern corner where the cliff edges are still covered in grass.

Adult Leach's Storm-Petrel on Outer Bald Island, Yarmouth County, July 31, 2016. Photo by Bertin d'Eon.

Juvenile Leach's Storm-Petrel on Outer Bald Island, Yarmouth County, July 31, 2016. Photo by Bertin d'Eon.

Bad Leach's Storm-Petrel egg on Outer Bald Island, Yarmouth County, July 31, 2016. Photo by Bertin d'Eon.

Future Work
I will be doing more Leach's Storm-Petrel surveys during 2017 and 2018 and hope to be able to get to some islands in Halifax and Guysborough Counties as well as the Bird Islands in Cape Breton. These birds are very interesting and difficult to monitor, so I am very fortunate to have the opportunity to do these surveys.

References
McLaren, I.A. 2012. All the Birds of Nova Scotia: status & critical identification. Gaspereau Press Ltd, Kentville, N.S., Canada

Oxley, J. R. 1999. Nesting distribution and abundance of Leach’s Storm-petrel (Oceanodroma leucorhoa) on Bon Portage Island, Nova Scotia. Thesis. Acadia University, Wolfville, Nova Scotia, Canada.

Pollet, I. L., R. A. Ronconi, I. D. Jonsen, M. L. Leonard, P. D. Taylor, and D. Shutler. 2014a. Foraging movements of Leach’s Storm-petrels Oceanodroma leucorhoa during incubation. Journal of Avian Biology 45:305-314.

Stewart, R.L.M., K.A. Bredin, A.R. Coururier, A.G. Horn, D. Lepage, S. Makepeace, P.D. Taylor, M.-A. Villard, and R.M. Whittam (eds.). 2015. Second Atlas of Breeding Birds of the Maritime Provinces. Bird Studies Canada, Natural History Society and Prince Edward Island, Nature New Brunswick, New Bunswick Department of Natural Resources, Nova Scotia Bird Society, Nova Scotia Department of Natural Resources, and Prince Edward Island Department of Agriculture and Forestry, Sackville, 528 + 22 pp.

Tufts, R.W. 1986. Birds of Nova Scotia. 3rd ed. Nimbus Publishing Ltd. N.S. Museum. Halifax, N.S. 478 p.