MONTEREY BIRDS
 

Canada Goose
Branta canadensis
&
Cackling Goose
Branta hutchinsii

 

 

Page One

 

a web page by Don Roberson
 
Canada Goose (above left) & Cackling Goose (above right), Moonglow Dairy 16 Dec 2004 © Jeff Poklen
 
 
Lesser Canada Goose (left) & Ridgway's Cackling Goose (right)
17 Jan 2009 near Salinas © D. Roberson

Here in coastal central California (including Monterey County) we don't usually have much trouble picking out a tiny Cackling Goose from among the huge resident population of Canada Goose. But things are more complex than that. There are two subspecies of Cackling Goose that occur as migrants and winter visitors — Aleutian Cackling Goose B. h. leucopareia and Ridgway's Cackling Goose B. h. minima — and there are migrant races of Canada Goose that are much smaller than our resident birds. Migrant Canada Goose can be much closer to the size of Cackling Goose (photo just above). Further, there are additional subspecies of both Canada and Cackling Geese that have not yet been confirmed for Monterey County, but that could occur in the future. We need to get a handle on all of them. In putting together this web page, I relied heavily on the identification criteria published by Mlodinow et al. (2008) and in the on-line sources cited at the end of this project. Mlodinow et al. (2008) coined the name Ridgway's Cackling Goose for the smallest subspecies of Cackling Goose, minima. It is the one subspecies that had no common English name. For purposes of this project, I'll use these names. listed from the largest to the smallest geese:

  • Giant Canada Goose B. c. maxima: originated in eastern United States but widely introduced across North America
  • Moffitt's Canada Goose B. c. moffitti: breeds primarily in Great Basin, and winters throughout California, but introduced or naturalized in western suburbia
  • Dusky Canada Goose B. c. occidentalis: breeds coastal Alaska (Copper R. delta), winters to northern California
  • Lesser Canada Goose B. c. parvipes: breeds interior Alaska and western interior Canada, winters California to Texas
  • Taverner's Cackling Goose B. h. taverneri: breeds tundra Alaska, winters Washington to central California
  • Aleutian Cackling Goose B. h. leucopareia: breeds primarily Aleutian Islands, winters San Joaquin Valley, California. Once considered an Endangered species but has responded well to the elimination of non-native foxes on its nesting islands, and was de-listed in 2001.
  • Ridgway's Cackling Goose B. h. minima: breeds in the Yukon-Kuskokwim Delta of western Alaska and winters from Oregon to California's Central Valley

Note that the first four subspecies are assigned to Canada Goose, and the final three to Cackling Goose.

The first step in understanding these white-cheeked geese is to be very familiar with our local Canada Goose (right). Here in MTY, the nesting Canada Geese are not native. They belong to an introduced population that was first noticed in the 1980s, and that has spread throughout the county. Hundreds now breed from Moss Landing to Big Sur (see Roberson & Tenney 1993 for more details on this expansion).

Photo (right) 15 May 2008 El Estero, Monterey
Photo (below) nesting 13 Apr 2007 Carmel R. mouth
both © D. Roberson

Some of these nesting birds (left) are huge geese with long necks, a long sloping forehead that continues its 'line' into the bill (recalling Canvasback in shape), and whitish breasts. These look very much like Giant Canada Goose.

However, as they are not native, we are not sure how to assign these resident geese to subspecies. Moffitt's Canada Goose has been suspected to be the origin of many western resident goose population, but the bird shown (left) looks pretty much like Giant Canada Goose. It is possible that the origin of our local residents includes a mixture of subspecies.

In addition to our breeding population of Canada Goose, migrants from northern or interior populations pass through during migration, and some may winter. We know that flocks of several hundred have wintered on Lake San Antonio, but it is now much more difficult to distinguish between migrants and resident birds, because our residents are so widespread.

For example, this Moffitt's Canada Goose was at the tip of Pt. Pinos 21-23 Jan 2009. It was feeding on detritus washed up at tideline, and not interacting with pairs of resident birds flying by. Could this be a wild migrant? Maybe . . . or maybe not. There is no good way to know. It does have a demarcation between the bill and the steeper forehead, unlike some of our breeding birds, but so do others that nest here. We suspect that wild Moffitt's Canada Goose is our most common migrant, but it is now very hard to separate them from resident birds. This individual, though, did show the flexible neck possessed by these big geese (above right).

A small number of our migrant Canada Goose are of the interior Alaskan race parvipes, known as Lesser Canada Goose. These birds can be half the size of our resident Canada Geese. And other races may also occur. Most Lesser Canada Goose are pale-breasted but some can be quite dusky.
migrant Canada Geese, race??
Lower Klamath NWR
Lesser Canada Goose B. c. parvipes
near Anchorage, Alaska
Dusky Canada Goose B. c. occidentalis
Halfmoon Bay, San Mateo Co.
Feb 1981 © D. Roberson
16 Apr 2007 © Stacy Jon Peterson
18 Jan 2007 © Jeff Poklen
The dark-breasted Dusky Canada Goose B.c. occidentalis has been recorded just north of us along the coast (photo below right). It is, however, a reasonably large Canada, as is obvious when it is next to a Ridgway's Cackling (above © Jeff Poklen, 18 Jan 2007 Halfmoon Bay). So size will be an important criteria in identifying the various races of these two species. More on that below; see also the very nice charts of comparative sizes (culmen length, mass) of all subspecies of both Canada & Cackling Geese in an on-line article by David Sibley [his commentary is only preliminary, but his charts are quite nice and derived from Mowbray et al. 2002].

But size is not enough. Through the magic of PhotoShop, I've moved a Lesser Canada Goose to a spot between two of our resident Moffitt-like Canada Goose (left). It looks really small between the two big geese. That does not make it a Cackling Goose. [The original photo, with the Lesser Canada in its actual location, is shown farther down this page.]

To clearly separate Canada from Cackling Geese we need to look at other characters, such as bill size and shape:
top: © D. Roberson, Carmel R. mouth
just above: © Stuart MacKay, Washington

Canada Goose (left)
large resident birds (upper)
migratory parvipes (lower)

Cackling Goose (right)
Aleutian (upper)
Ridgway's (lower)

Bill size & shape

Both absolute and relative bill length and shape are key features separating Canada Goose and Cackling Goose but, as you can see, there is variation in length depending on the subspecies involved. In all cases, though, the smallest Canada Goose has a longer bill than the biggest Cackling Goose. Further, Canada Goose bills are drawn-out, being much longer than deep, while Ridgway's Cackling Goose has a triangular-shaped bill (lower right): depth and length are similar.

top: © D. Roberson, Crespi Pond
just above: © Jeff Poklen, Pajaro R. mouth
Size, bill shape, and breast color are important characters, and are best analyzed when there are various geese to compare. Here are six geese near Salinas on 21 Jan 2009. The three standing on dry ground are very large, with long bills and white breasts. They are either Moffitt's Canada Geese or a moffitti/maxima mixture, just like our resident birds. Standing in water are three decidedly smaller geese. The lefthand bird is very small and has a very dark breast; the next one is also very small but has a paler breast, and the third one (to the right of the first big goose on shore) is a bit larger and has even a paler breast. All three of the small geese of white neck collars of varying widths.

Let's look at the three small geese more closely (above), and compare with a Ross's Goose (extreme left). The lefthand dark goose is the size of Ross's, has a very dark, almost purplish-brown breast, and a very short triangular bill. It is Ridgway's Cackling Goose. The center dark goose is decidedly larger, has a bill that is obviously longer than deep, and is quite white-breasted. It is shown in flight next to the Ridgway's in the next to top shot on this page. I've shared these shots with Steven Mlodinow and Bruce Deuel, co-authors of Mlodinow et al. (2008), and they agree this center dark bird is most likely a Lesser Canada Goose B.c. parvipes. It is only half-the-size of the big Moffitt-like Canada Geese. This particular bird has a very broad white neck collar, which is unusual. Most parvipes don't have neck collars, but Deuel points out that a small percentage do (8% in the study by Johnson et al. 1979). The pale breast is typical of parvipes, so only the collar is unusual.

This leaves the other small dark goose which is facing us (far right, above), so we can't see bill shape, but it is mid-size between the other two, has a medium-dark breast (not as dark as Ridgway's), and has a medium white neck ring. We can, however, evaluate it better in flight (below). The Lesser Canada is still in the center, and obviously the largest with the bigger bill. The tiny, very dark-breasted minima is now to the right, and the third mid-sized goose is now to the left. It clearly has a short bill but decidedly longer than minima, and it is decidedly larger. Our third dark goose is an Aleutian Cackling Goose.

We can confirm this all again in another shot with Ross's Goose as a comparative (above). From left: Lesser Canada, Ross's, Aleutian Cackling, and Ridgway's Cackling. Note again the difference in bill shape in the two Cackler's.

We'll get into more depth in separating between races of Cackling Geese in the second page of this project:

Literature cited:

Johnson, D.H., D.E. Timm, and P.F. Springer. 1979. Morphological characteristics of Canada Geese in the Pacific Flyway, in Management & Biology of Pacific Flyway Geese (R.I. Jarvis & J.C. Bartonek, eds). Oregon State Univ., Corvallis, OR.

Mlodinow, S.G., P.F. Springer, B. Deuel, L.S. Semo, T. Leukering, T. Doug Schonewald, W. Tweit, and J.H. Barry. 2008. Distribution and identification of Cackling Goose (Branta hutchinsii) subspecies. North Amer. Birds 62: 344–360.

Mowbray, T.B., C.R. Ely, J.S. Sedinger, and R.E. Trost. 2002. "Canada Goose" in Birds of North America, No. 682 (A. Poole & F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Pyle, P. 2008. Identification Guide to North American Birds. Part II. Slate Creek Press, Bolinas.

Roberson, D. 2002. Monterey Birds. 2d ed. Monterey Pen. Audubon Soc., Carmel CA.

 
 

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