Tuesday, December 29, 2015

Mountain Bluebirds, Mountain Bluebirds, Mountain Bluebirds.

It is clear that 2015 has been a tremendous year for Mountain Bluebirds in Nova Scotia. Many of our birders were able to add this western open-habitat thrush to their provincial list. These visiting rarities have been long-staying and have for the most part stuck to small areas making them easy to find.

2015 Timeline
Important observations of Mountain Bluebirds this year are listed below in chronological order:

  • Nov 15 - Simon-Paul d'Entremont photographed two bluebirds at Mavillette, Digby County. They were assumed to be Eastern Bluebirds at the time.
  • Nov 22 - David Bell and Dominic Cormier discover a hatch-year (HY) female Mountain Bluebird at Freeport, Digby County. See the eBird Checklist for photos.
  • Nov 22 - David Bell and Dominic Cormier find a HY male Mountain Bluebird at Mavillette, Digby County. See my eBird Checklist for photos from that day.
  • Nov 28 - Richard Hatch saw three bluebirds at Mavillette, Digby County, that he identified as two Mountains and one Eastern. No photos were taken that day and multiple birds were not observed again at Mavillette until Dec 26, see this item below.
  • Dec 2 - Cal Kimola Brown found a HY male Mountain Bluebird at Fish Plant Rd, Cape Sable Island, Shelburne County. The bird at this location was never resighted.
  • Dec 6 - Alix d'Entremont got two HY male Mountain Bluebirds (Fig. 1) at Church Hill Rd, Cape Sable Island, Shelburne County (only 0.5 km away from the Dec 2 sighting). One is likely the same that was photographed nearby on Dec 2 by Cal Kimola Brown. See my eBird Checklist for photos.
  • Dec 26 - Simon-Paul d'Entremont photographed two Mountain Bluebirds at Mavillette, Digby County. One is a HY male, and the other, a HY female.
A few questions arrise from the list of observations above.

What explains the lack sightings of multiple birds at Mavillette after Nov 28 and before Dec 26? The Mountain Bluebird at Mavillette was consitenty found at the Cape View Motel and Restaurant, but would sometimes dissapear to the south-east in the large expanse of coastal alders. Was this where the others were spending time?

Were the three bluebirds seen on Nov 28 comprised of the one HY male Mountain Bluebird and one Eastern Bluebird photographed on Nov 15 in addition to the HY female Mountain Bluebird from Freeport (Fig. 2)? Freeport is only 25 km from Mavillette, so that seems very possible also given that the age and sex of the bird is the same. In order to survive, vagrant birds will linger at good locations where they can find enough food. Mavillette, with its open landscape, appears to be an appropriate place for these bluebirds.

Figure 1. Two hatch-year male Mountain Bluebirds at Cape Sable Island, Dec 6, 2015. Photo by Alix d'Entremont.

Figure 2. Hatch-year females at Mavillette (Dec 26, 2015) and Freeport (Nov 22, 2015) that might be the same individual. Photos by Simon-Paul d'Entremont and David Bell.

There is precedence in Nova Scotia of different bluebird species in one location. On Jan 18, 1999, a Mountain Bluebird (present since Jan 16) in Centreville, CSI, was joined by an Eastern Bluebird. Both birds remained until at least Feb 7, 1999.

Historical Sightings in NS

I've combined all issues of NS Birds (previously named the Nova Scotia Bird Society Newsletter and later Nova Scotia Birds) into a 1.6 Gigabyte PDF complete with searchable text. This allows me to search by species name and find all occurances quickly.

  • Oct 25, 1989 - possible female at Hartlen Point, HRM.
  • Jan 27 - Feb 10, 1992 - our first fully confirmed, a HY male in Brooklyn, Queens County.
  • Jan 10, 1995 - female at Sable Island, HRM.
  • Jan 3, 1999 - immature at Port Morien, CBRM.
  • Jan 16, 1999 - female at Cape Sable Island, Shelburne County.
  • Nov 14-15, 2002 - female at Cape Sable Island, Shelburne County.
  • Dec 22-24, 2002 - one at Little River Harbour, Yarmouth County.
  • Jan 15-17, 2003 - one at Cape Sable Island, Shelburne County. *same as the Nov 2002 bird?*
  • mid-April, 2005 -  one at Long Island, Digby County. (7th)
  • May 23, 2007 - one in Upper East Green Harbour, Shelburne County.
  • May 10, 2009 - one in Dartmouth, HRM.
  • Dec 31, 2011 - one in Glace Bay, CBRM.

The above results in a total of 12 reports. There is a high probability that the Jan 2003 sighting was the same bird that was seen in Nov 2002. We are now left with 11 historical occurances of Mountain Bluebird in Nova Scotia. There have been at least 4 during 2015 (assuming the Freeport and Mavillette HY females are one in the same), the conservative total becomes 15. Twelve records have been during fall/winter and the remaining 3 in spring.

Migration and Vagrancy

Mountain Bluebirds are the most migratory of the bluebirds. They breed from east-central Alaska in the north to extreme west Texas in the south. They winter as far south as central Mexico and north to north-central Oregon. Depending on the severity of winter, they concentrate in the nothern of southern potion of the winter range. Autumn migration begins in August and extends into November. (Power & Lombardo, 1996)

The unprecedented number of Mountain Bluebirds in Nova Scotia during late fall and winter 2015 are mirrored by multiple sightings in other parts of eastern North America. Below are the number of Mountain Bluebirds reported to eBird in other eastern provinces and states.

  • Ontario - 2
  • Quebec - 1
  • New Brunswick - 1
  • Massachussetts - 1
  • Florida - 1

Figure 3 compares the eBird reports from fall migration 2014 to those of 2015. These maps allow us to visualize a phenomenon of vagrant Mountain Bluebirds that was not confined to NS. It is fair to say that a specific weather pattern at a particular latitude, altitude and time played a role in the arrival of the Mountain Bluebirds to eastern North America. During August and early September, we get airflow from the southwest. October through December is characterized by zonal airflow across North American from west to east, directly towards our province. This wind pattern contributes to the yearly arrival of birds from the west. (McLaren, 2012)

Another cause of vagrancy is misorientation, but the effect would be more consistent from year to year. A quick look through eBird shows that significant numbers of Mountain Bluebirds in the east, similar to the 2015 event, don't occur on a regular basis. The last time that we saw large numbers was during fall/winter 2011/2012.

Figure 3. Late fall/winter Mountain Bluebird eBird reports from 2014/2015 (left) vs late fall/winter 2015. From eBird.org.

Fall and winter 2015 were characterized by many other notable western vagrants to our province; these include Hermit Warbler, many Western Kingbirds, Bullock's Oriole, two American White Pelicans, an apparent "western" Marsh Wren and Western Flycatcher (Pacific-slope or Cordilleran).

One Mountain Bluebird in Nova Scotia is thrilling enough, but two separate locations with two individuals is amazing. Nova Scotia keeps providing evidence that it is truly a great place for vagrant birds. Its location (halfway between the north and south poles) and geography (surrounded by water and comprised of many headlands and islands) are great for producing exciting birding. (McLaren, 2012)


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

Power, Harry W. and Michael P. Lombardo. 1996. Mountain Bluebird (Sialia currucoides), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/222

Tuesday, December 8, 2015

A Three Lifer Day

At 5 am on Dec 5, 2015, I picked up Ervin Olsen and Mark Dennis by car and we drove east on Highway 103. The plan was to drive up to Shubenacadie to twitch on three good birds that had been reported in the area. These three species were all lifers for me, so a long day of driving would be worth it. Eight Sandhill Cranes (Grus canadensis), and one each of Greater White-fronted Goose (Anser albifrons) and Cackling Goose (Branta hutchinsii) were within a 15 minute drive of each other.

We made great time and reached Snides Lake, a 29 acre water body near Exit 10 in Shubenacadie, by 8:15 am. We were on the northern side and all of the waterfowl were on the opposite end (Fig. 1). After a bit of searching, Mark found the Greater White-fronted Goose. We looked around a bit more for the Cackling and decided to drive closer to the geese and try for a photo.

Figure 1. Mark Dennis and Ervin Olsen looking through the hundreds of geese at Snides Lake, Hants Co., Dec 12, 2015. Photo by Alix d'Entremont.

This new vantage point provided much better views of the rare goose. It appeared fairly small compared to the Canada Geese that surrounded it (Fig. 2). The orange bill is very obvious through the scope, even at a distance of over 600 m. Mark shared with us that Greater White-fronted is quite easy to spot by checking for its orange legs when in a standing group of Canadas.

Figure 2. Greater White-fronted Goose with Canada Geese at Snides Lake, Hants Co., Dec 12, 2015. Photo by Alix d'Entremont.

This individual is a juvenile and lacks the adult's distinctive white band around the bill and on the forehead. The most expected subspecies in Nova Scotia is the "Greenland White-fronted Goose" A. a. flavirostris. This population normally migrates to Europe, but increasingly occurs in n.e. US and Atlantic Canada.  This bird fits for flavirostris as it shows a distinctly orange bill and lacks the grayish back tones and pinkish bill shown by A. a. gambelli, the subspecies that breeds across n.w. Canada (Fig. 3). (McLaren, 2012)

Figure 3. Juvenile Greater White-fronted Goose at Snides Lake, Hants Co., Dec 5, 2015. Photo by Alix d'Entremont.

Timing was right when I received a call from Andy de Champlain as he stood on the Milford Rd admiring the group of eight Sandhill Cranes (Grus canadensis). Merridy Rankin accompanied Andy and Fulton Lavender and offered to meet us at Snides Lake and lead us directly to the cranes. We arrived at the Milford Rd location and the flock of eight was my second lifer of the day.

Figure 4. Eight Sandhill Cranes on the Milford Rd, Halifax Co., Dec 5, 2015. Photo by Alix d'Entremont.

Both the Greater (G. c. tabida) and Lesser Sandhill Cranes (G. c. canadensis) are reported to have occured in the province. Most references warn that subspecific indentification should only be attempted on individuals that are on the extreme ends of the proportional differences between subspecies (McLaren 2012, Alderfer 2014). Compared to Greater, Lesser Sandhill Cranes are smaller and have relatively shorter legs and neck. McLaren (2012) gives us a rule of thumb: the bill of tabida is about twice the length of the head, that of canadensis about the length of the head. G. c. rowani represents a population that is between canadensis and tabida in both breeding location and structure.

The bill length of most birds appear to be closer to the length of the head than twice the length of the head. There has been some subspecific discussion of these cranes on the NSBS Facebook Group, but nothing that I would call concrete. For some "light" reading regarding Sandhill Crane subspecies, there is a 2001 article that Maxine Quinton forwarded to me named Mitochondrial Phylogeography, Subspecific Taxonomy, and Conservation Genetics of Sandhill Cranes (Grus Canadensis; Aves: Gruidae) that is interesting.

Twitching birds often provides opportunities to see birders from other parts of the province that you don't often get to spent time with. We took the opportunity to grab a few photos, like the one in Figure 5.

Figure 5. Andy de Champlain, Fulton Lavender and Alix d'Entremont (me). Photo by Ervin Olsen.

Once we had our fill of photos and scope views of the Sandhill Cranes, Andy and Fulton followed us to the next water body where we hoped we'd find a Cackling Goose. It had been seen at at a pond just south of Shubenacadie near the railroad tracks. Eric Mills called it Shaws Pond on eBird, so that is what I'll go with. The five of us arrived and soon after we were joined by another Nova Scotia Bird Society member, Donna MacNeil. We crossed the railroad tracks (carefully looking both ways) and Mark soon found our target bird.

Once I got my binoculars onto the Cackling Goose, I first noticed how how pale it was and then how small it was in comparison to the Canada Geese (Fig. 6). Switching optics often resulted in the temporary loss of the subject. I finally was able to get my camera on it and get a few photos.

Figure 6. Cackling Goose among Canada Geese at Shaws Pond, Hants Co., Dec 5, 2015. Photo by Alix d'Entremont.

Cackling Goose (Anser hutchinsii) was only split from Canada Goose (Anser canadensis) in 2004 in the 45th Supplement of the AOU Checklist. The split occured due to differences in size, voice, habitat and timing of migration (Mowbray et al., 2002). In general terms, it looks like a small Canada Goose, almost how Ross's Goose is a tiny version of a Snow Goose. If you were to shrink a typical Canada Goose, you still wouldn't have a Cackling. In comparison to Canada Goose, Cackling Goose has a relatively shorter neck, smaller bill and steeper forehead (Alderfer, 2014).

The only subspecies of Cackling Goose that is expected in Nova Scotia is "Richardson's Cackling Goose" A. h. hutchinsii (McLaren, 2012). This population breeds from the Mackenzie River Delta to Baffin Island and south to n. Hudson Bay, migrates mid-continent and spends the winters in the south-central US (Mowbray et al., 2002). The other three subspecies breed west of hutchinsii and also winter further west (Alderfer & Dunn, 2014).

A three lifer day in Nova Scotia is getting harder as my species list climbs. I may have to wait for a storm during spring or fall migration for this to happen again.


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

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

Pyle, P., S.N.G. Howell, R.P. Yunick, and D.F. Desante. 1997. Identification guide to North American Birds, Part 1, Columbidae to Ploceidae. Slate Creek Press, Bolinas, California.

Mowbray, Thomas B., Craig R. Ely, James S. Sedinger and Robert E. Trost. 2002. Canada Goose (Branta canadensis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/682