Wednesday, August 26, 2015

Avian Vagrancy in the Great Lakes: Brown Booby

Fort Erie, Ontario. October 2013

Avian Vagrancy in the Great Lakes - a look at vagrant bird species that have occurred in and around the Great Lakes Basin. These notes look at the status and distribution of the species, identification, trends in occurrence, hypothesize on factors influencing their occurrence and what the future may hold for the species in the region.

This is not a complete account of all known records. Records have been retrieved from the following databases:

MOURC - Minnesota
WSORC - Wisconsin
IORC - Illinois
IBRC - Indiana
OBRC - Ohio
PORC - Pennsylvania
NYSARC - New York
OBRC - Ontario

I encourage birders to support their representative bird records committee. Having readily accessible records data allows people to rapidly research topics of interest or produce documents/products that others can learn from or expand upon. Having all databases uploaded to eBird may one day provide the most effective way to conduct these studies. If you know of additional records not found in these sources, please leave it in the comments section below. Additional species accounts on avian vagrancy in the great lakes region will continue.


Brown Booby Sula leucogaster

Two records:

October 2013 - New York & Ontario

7 October - 2 November, 2013, Buffalo, Erie and Fort Erie, Niagara. (Niagara River) Photos. Definitive alternate female, leucogaster. Also at Long Point, Ontario and Lowbanks, Ontario.

Holden, B.R. 2014. Ontario Bird Records Committee Report for 2013. Ontario Birds 32(2):54-81. Available online at

August 2014 - New York & Vermont

23 August - 9 September, 2014. Lake Champlain, Various. Photos. Female.

VERMONT BIRD RECORDS COMMITTEE - COMMITTEE REPORT – 25 October 2014. Annual Reports from the Vermont Bird Records Committee. 3pp. Available online at

This stunning sulid hails from the tropical waters of the Americas, but has increasingly shown a penchant for wandering. Even considering the species vagrant tendencies, a record in the Great Lakes was truly remarkable. An individual here would have traveled at least 1800km from the species core range to reach our region. The spectacular size and structure and habits would lend to a high detection rate; although an increase in records beyond the species normal range has been a recent phenomenon making it challenging to detect any patterns in occurrence or predict the future of the species in our region.

Distribution of Brown Booby records in the Great Lakes Basin.

Documentation: A report of this species in the Great Lakes region is likely to receive great scrutiny. Thankfully the distinctive appearance should lend itself well to a written report. A large species with a five foot wingspan, birders could focus on structure to help eliminate most other species. Pointed at both ends, and long pointed wings recall Northern Gannet, which may be the only species truly requiring separation; although birders would be served well to eliminate gulls, pelicans, herons and perhaps frigatebirds for good measure. Adult plumages are sharp and contrasting; brown and white, with obviously pale bills. Juvenile and subadult birds can be surprisingly dull. Time of year may be a useful separating factor between this age and juvenile Northern Gannet - more expected on the cold days of November. Observe the juvenile Gannet's cold, dark and speckled plumage; especially the white U on the uppertail coverts. Notes on fine plumage details and overall impression will be heavily relied upon for the surprisingly plain juvenile Brown Booby; ensure you see warmer brown tones to the plumage! The two regional records are of adult (or near adult) females, and are well photographed.

Detection: both records had a prolonged stay, and was detected at three or more well spaced locations on Lakes Erie and Champlain. This is a species that would draw the eye of the most casual observer; even without its propensity for landing on boats of all sizes. This combination of striking features and occurrence in close proximity to human activity indicates a high detection rate; with the two records likely being a more accurate representation of occurrence in our region, relative to other vagrant bird species.

Weekly detection and occurrence of the Brown Booby throughout the calendar year.

Factors of Occurrence: It is difficult to detect any factors or trends in occurrence with single records; but as a subtropical oceanic species it is not a stretch to assume that tropical cyclones and their remnants may be primary factors in bringing an individual to our region. The initial date of the 2013 occurrence falls in early October; subsequently staying for nearly a month. Long-staying individuals decrease the confidence in tying any meteorological influences in occurrence; as it becomes harder to know when exactly the bird arrived on our shores. With the 2013 record in the Great Lakes, I somewhat arbitrarily believe that October 7th was the true arrival of the bird on Lake Erie, due to a combination of the account of the finders of the bird (who also believe it was a fresh arrival) and the meteorological conditions associated with the date it occurred. Reproduced below is a CONUS surface analysis from October 6th, 2013. In the Gulf of Mexico we can see the post-tropical remnant low of Tropical Storm Karen and a 1003mb low pressure centre over the Great Lakes. A potential meteorological explanation is complex, as both systems are relatively weak; where Karen entrained and/or displaced the Brown Booby inland, where it was then adrift overland. Once over land the Brown Booby may have followed the strong winds associated with the converging air masses towards the low pressure in the Great Lakes. After such a flight; the waters of Lake Erie were perhaps relatively welcoming; with the strong southwest winds of October 7th bringing the bird to the Buffalo/Fort Erie area. Such a complex explanation would be impossible to prove; yet such unique circumstances may be required to bring such an outlandish bird to the Great Lakes. 

CONUS Surface Analysis on 1200z 6 October 2013

The 2014 record is problematic to place. Initially detected on 23 August; there was little significance from a meteorological perspective on both this day and the days preceding it. Noteworthy is another weak low pressure system in close proximity to the occurrence on Lake Champlain. If August 23rd was the birds true arrival in the region; then it is possible that east winds brought the bird from the nearby Atlantic seaboard - from one vagrant location to another. There is potential that an individual vagrant bird is perhaps MORE susceptible to changes in weather (and additional vagrant flights) than resident birds; but this may require more research. Reproduced below is the surface archive for August 22, 2014. 

CONUS Surface Analysis on 1800z 22 August 2014

Future records: The Atlantic Hurricane season officially runs from June 1 - November 30th, however there is a pronounced peak of activity from mid August through early October. The great irregularity of storms affecting our region means that birders can focus their efforts during specific events; rather than by following the calendar. An increase in vagrancy records along coastal shores is a poorly known phenomenon; and other (exceptional) inland records may be likely as shown by the 2014 record which may not be tied to significant meteorological events. If current trends continue then additional records may be possible; however any change in pattern could halt current trends and once again making the Brown Booby an unthinkable visitor to our shores.     

It will be interesting to monitor the future of the Brown Booby in the Great Lakes region and elsewhere throughout North America. A high detection rate will help to paint a clearer picture as time passes; with or without additional records. The August-October timeframe appears most likely for future records; yet June and July should also be considered. I would like to thank those that continue to document unusual bird observations, which were invaluable in creating this account. If you know of any additional records, references or new thoughts on the status of the Brown Booby in the Great Lakes, please leave it in the comments below. This account can and will be updated going forwards.

Fort Erie, Ontario. October 2013

Roy, K. 2014. Brown Booby New to Ontario. Ontario Birds 32(2). Available online at

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