posted October 20th, 2009; last edited April 8th, 2010 –– David Sibley

Ageing Canada Geese

Determining the age of a goose can be helpful for identification, and can also reveal some interesting behavioral and ecological information by enabling you to sort out family groups and subflocks. Given good views it’s not hard to distinguish Canada Geese that are still in juvenal plumage from those that are in adult plumage. By October many immatures (hatched in the summer a few months earlier) will have molted most of their body feathers into adult-like plumage, while others have not yet begun to molt. In general, consistent with other species of birds, the late-molting juveniles are long-distance migrants from far northern breeding grounds, while local Lower-48 resident Canada Geese molt in early fall.
Differences apparent in these photos are:

  • Juvenile overall has lower contrast markings, especially blurry and obscure pale edges on back feathers
  • Juvenile has all feather tips narrow and rounded, vs adult feather tips broader and more square or flat-tipped. This creates a strongly barred pattern on the adult with pale lines straight across the back and well-marked pale and dark bars on the flanks.
  • Juvenile has neck not quite as dark blackish as the adult, and the dark neck blends into the paler breast color; vs the adult has a truly black neck (in shadow in the lower photo here) with very distinct edge and no blending to pale breast (but in some dark western subspecies the black neck may blend into a dark brown breast even on adults)

Similar differences in feather shape and pattern should allow ageing of other species of geese as well.

Anser_canadensis_age

Juvenile (top) and adult (bottom) Canada Goose. 19 Oct 2009. Concord, MA. Photos copyright David Sibley.

8 comments to Ageing Canada Geese

  • OpposableChums

    Fascinating. A bird ID opportunity right in front of me all the time, and I was unaware.

    I'm heading over to the Hudson.

    Many thanks.

  • Kirk Mona

    Good Stuff. I think people tend to ignore Canada Geese as being common or, even worse they simply call them "sky carp." They are really quite beautiful in the same way of the subtle beauty of a sparrow. Thanks for another excuse to look closer.

  • Toronto real estate agent

    Quite beautiful indeed! I used to watch them all day long by the lake we had by our house when I was little. I even thought they were prettier than swans…haha. Even today, I think they have something magical about them.

    Take care, Julie

  • Hilke Breder

    Now I have another reason to check out Canada Geese, other than looking for a Cackling goose. Makes looking much more interesting. They are really quite beautiful birds.

  • Neil Robins

    Hi,

    I went birding with the Tuesday bird walk up to Deep Bay on Vancouver Island in British Columbia, we saw some very unsual Canda geese—

    The Tuesday bird walk went to Deep Bay. The morning was cold with snow flurries and a strong biting wind off the Strait of Georgia. The highlights included seeing a Cackling Goose in with a flock of mostly Richardson’s Race and Common Canada Geese. Three of the Canada Geese were very unusual. They were light coloured with a dusting of white on their brown necks and heads, rather than the usual black heads and necks.

    I have never seen these colour’s in Canada Geese before.

    Do you have any ideas?

    Cheers
    Neil Robins
    Parksville
    British Columbia

    • Hi Neil, This sounds like “dilute” plumage, often called leucistic. Birds with this condition either produce only one type of melanin or only deposit small amounts of melanin in their feathers. This can be caused by problems with the production of melanin or with the deposition of melanin, and in this case it is affecting all feathers equally, so that the bird shows the normal pattern of dark and light, just very washed out. Aviculturists call these variations “fawn” or “Isabelline” among other terms.

  • Neil Robins

    Thanks for the information!

    Neil

  • Ettina

    I was wondering if there are any tricks that can be used to identify individual Canada geese by sight. On two different days I filmed a family of two geese and six goslings in the same area, and while I strongly suspect they’re the same birds, is there any way to know for sure? (For example I know from Big Cat Diaries that lions’ whisker spots are as unique as fingerprints – do geese have any really individualized markings?)

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