Just how punctual are the Buffleheads anyway?

First Migrants Shoal Harbour Sanctuary (Submitted by K.J. Finley)

11 October, 2017

Its charting season again so I’m pleased to present the latest phenogram of first arrivals to Shoal Harbour Sanctuary.

First, a word about the methodology. Although the scientific constant of All Buffleheads Day is said to be merely the product of “citizen science”, its methods are exacting, and the results testable and repeatable. It looks simple, and is, but does not follow the typical protocol of stratified, randomized measurements from several observers and locations. In part this is because science is agenda-driven with limited horizons, while my retirement “hobby” is not, until death at least. So this is my second lifetime study, after the Bowhead, and Roberts Bay is my stage, with a spectacular 180 degree panorama of a discrete pocket bay and the offshore waters of Sidney Channel.

This is my laboratory and microscope. Its like having a Hubble view through a dense cloud of random observations. One position, same observer, focused on the Bufflehead.

Arrival Phenology Shoal Harbour copy

Figure 1

Figure 1 illustrates the average arrival time of fourteen other species, for the last seven years, including this season. To date all except the Bufflehead and Greater Scaup have made their appearance. Note the Bufflehead’s position ( Large RED dot), second to last, ahead of the Red-breasted Merganser.

Beginning in late July with the arrival of boreal and prairie gulls, hooded mergansers and mallards, and the crush of migrants in late September from the prairies, the Bufflehead stands out as a solitary figure in mid-October.

Variation in Arrival Date copy

Figure 2


Figure 2, the histogram, tells the story of the Punctual Bufflehead. It is five times more precise than the average of all other species.

Today, (October 11) the first White-winged Scoters (2) and a single Red-breasted Merganser appeared. We are now in the narrow window around ABD.

Editor’s Note: Finley’s personal observations from his vantage point on Roberts Bay offer convincing evidence that Bufflehead ducks are indeed more “punctual”  than other species as to arrival times at their over-wintering sites. On October 14 (Bufflehead Welcoming Ceremony on Roberts Bay) and on October 15 (boat tour from Victoria to Sidney and back) with many observers on hand, no buffleheads were sighted. According to Finley’s observations, these are prime days for observing the first arrivals of Bufflehead ducks to this area.

On October 18, with no Buffleheads in view on Roberts Bay, K.J. Finley pointed out that “punctuality” notwithstanding, migrations are weather-dependent (Figure 3).

Microsoft Word - Day 300 of Vigil.docx

Figure 3

A local resident reports sighting one male and two female Buffleheads off Lands End Road in North Saanich on October 23, a date that would not significantly distort the synthesis of Figure 2 were these birds to be the first of their species to arrive.  In any event, we are reassured that the Buffleheads are back.


Editor’s Note continued:

This just in from K.J. Finley. It fits nicely with the previous discussion.

CONGRATULATIONS AND HAPPY BIRTHDAY TO OUR SISTER SANCTUARY (Victoria Harbour Migratory Bird Sanctuary). We are synchronous with ABD, though a tad late. To celebrate, I bring the first spaghetti chart to the seasonal banquet.

“If you would become familiar with a bird, you must live with it, day by day through the seasons, following the activities that fill its life and add up to the picture conjured by its name. So it is with the Bufflehead. Where they linger around a residential area, as in Victoria, British Columbia, and Boston, Massachusetts, this is easily done. People fortunate enough to live on the water’s edge may watch Buffleheads from their tables, and others can do so from a parked car on the streets that wind along the shore.” Dr. Anthony Erskine, “Buffleheads” Canadian Wildlife Service 1971


Spaghetti Chart 1 : First Influx October 26th, 2017. Horizontal axis : dates in October. Vertical axis: estimates of the number of Buffleheads in the area

As expected, the first significant influx of Buffleheads has appeared on this crisp, clear, calm day, as a ridge of high pressure sets up over the Pacific Coast, and a record setting storm October threatens the Atlantic Coast.

The RED line illustrates the Bufflehead’s tardiness this season, compared to last year’s rapid early, mass influx, and the average rate of influx.


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