Canada geese, you may have noticed, are everywhere these days.
With the summer breeding season over, these ubiquitous waterfowl are back in their flocks—a great winter survival strategy—and are teeming about cornfields, athletic fields and other grassy expanses. They’re also paddling around local wetlands and other water bodies, and in general making themselves hard to miss. Even at night, when you can’t see them, it’s not hard to know where they are—their honks and squawks give them away every time.
The birds and their sounds are unmistakable. And if you follow the old adage of “birds of a feather flock together,” it would be logical to think that all those geese belong to one homogenous group. After all, they certainly look the same. But looks, as they say, aren’t everything.
What we actually are seeing right now are two different groups, or subspecies, of Branta canadensis. Individuals of B.c. maxima, the giant Canada goose, make up our resident population. These guys are nonmigratory; that is, they may fly short distances in search of food, water or breeding territory, but they are present in the TriCities year round.
The other group is a migratory subspecies, B.c. interior, also known as the Todd’s goose or Hudson Bay Canada goose. These birds, identified as part of the Mississippi Valley subpopulation, arrived in our area a few weeks ago.
To the casual observer, the two subspecies appear nearly identical. True to its name, maxima is a little bigger; meanwhile, interior has a somewhat darker coloration, especially along the back. If you’re not familiar with the nuances of birding, these differences can be hard to spot.
But what’s easy to see is the birds’ behavior. Our resident birds, used to people, used to traffic and (unfortunately) used to handouts, hold their ground or shift away slowly when approached. The interior geese, however, are much more skittish. The slightest movement, cough or, in my case, click of a camera shutter, can spook a flock and send them airborne amid a din of honks and flapping wings.
It might not sound like a big deal, this business about goose subspecies. After all, the physical differences between the birds are minor, and the behaviors are, for most people, a novelty at best.
But for scientists who study birds, the migratory flocks are displaying some changes that may indeed be significant. Over the past several decades, these birds seem to have changed their habits with regard to migration. That is, they’re not flying as far south as they used to.
Migration for any species is difficult, and for a goose in particular a flight south could easily end up being its last. For one thing, hunting season is in full swing. Migration flights also are very physically taxing. Birds must be in top physical condition, and be able to find quality food, water and stopover habitats, all while avoiding predators and other threats along the way.
Luckily for the geese, it would seem that our area offers them much of what they’re looking for in overwintering grounds. Sure it still gets cold here, but cold to a goose is not that much of a threat. As anyone who’s ever worn a goose down coat will tell you, those soft under-feathers are great insulators.
Plus, our area offers two elements essential to geese, both resident and migratory: readily available food and open water. Leftover grain in farm fields is free for the taking, as is the turfgrass in our yards and parks. Combine this abundance with an absence of hunters and unfrozen stretches of river, and you end up with a chilly but otherwise Eden-like setting for both subspecies.
Which, for us, translates into a whole lotta geese.
Waterfowl ecologists are very interested in these prevailing trends, and considerable research is being conducted in the Chicago area to try and define just how many of our winter geese are residents, and how many are migratory. Only after these populations are characterized can effective management strategies be implemented.
This winter, researchers from Southern Illinois University will be in St. Charles collecting Canada goose DNA samples as part of a broader study examining goose populations in the greater Chicago metropolitan region. In addition to gathering data on population proportions, the scientists will be obsderving daily movements, food types and roost characteristics, and how weather influences these factors.
Pretty neat huh?
If you’re like me, and would like to learn more about the Canada geese in our area, as well as the research that will soon be underway, circle this Thursday, November 12 on your calendar. That day, from 7-8:30p.m., Hickory Knolls will host “Meet the Canada Goose,” a presentation by SIU graduate research assistant Kendra Slown. Kendra is not only deeply familiar with B. canadensis; she also is one of the researchers participating in the study.
The program is part of our Learn from the Experts program series, which is a cooperative effort between the St. Charles Park District, the Geneva Park District and the Forest Preserve District of Kane County. Fee is $10 per person and advance registration is much appreciated.
Got questions? Give me a call. We’re hoping for a big honkin’ crowd and would be delighted to have you here.
Pam Otto is the manager of nature programs and interpretive services at the Hickory Knolls Discovery Center, a facility of the St. Charles Park District. She can be reached at 630-513-4346 or potto@stcparks.org.
November 6, 2015
Canada Geese
They may look similar, but the flocks of geese currently present throughout the TriCities actually represent two different subspecies, the giant Canada goose and the interior, or Hudson Bay Canada goose. Research this winter will examine the dynamics of these two groups and help determine future management strategies.