Ah, sweet spring… the flowers are blooming and the birds are singing. What we perceive to be a peaceful, perhaps even tranquil, scene, however, is actually a war zone. Avian territorial boundaries are constantly being established, challenged, trespassed, defended and realigned. It’s a dynamic world out there!
So why all the fuss? Why not just share the area, build a nest and go about their daily lives? It goes back to the wonderful all-inclusive word called “habitat.”
Habitat is defined as the place where an animal will find adequate food, water, shelter and space to ensure a healthy and productive population. (I should know… that was my teaching lesson to elementary, secondary and post-secondary students over a couple of decades at the Wye Marsh and Tiny Marsh outdoor education centres.)
For a pair of birds to successfully raise a brood of fledglings they will need easy access to ample food, certainly a drink of water a few times a day, enough building materials for a nest, and a safe and secure place to build that nest. And they need space… perhaps better defined as territory… an area that contains all of the above requirements.
Each species has a list of elements that makes for a good home territory for itself and the kids. Once that special place has been found, then comes the task of defending it from jealous neighbours or late-comers to the neighbourhood. And this defence has to be maintained while going about finding nest-building materials, constructing said nest, and finding food to replenish their energy.
While birds are fabulous at nest construction, they are not very good at fence construction. So, an audible ‘fence’ needs to be established and maintained. When a bird sings, whether sweetly or coarsely, it is a proclamation that “This tree is mine!… So is this one… and this one… and this one!”
As it is becoming increasingly difficult for some species to find the good habitat they are seeking, there is often a dispute as to which side of the tree one territory ends and another begins. And if a summertime bird feeder is still being supplied, then several territories may overlap as each pair wants that “supermarket” to be handy within flying distance of their nest.
Generally speaking, territory boundaries are set out between pairs of the same species. Cardinal family A is over here while Cardinal family B is over there; Bluebird family A is over here while Bluebird family B is over there. Again, due to the absence of a good fence, there may be misunderstandings as to just how far down the hedgerow Family A has its claim; should members of Family B have the audacity to scrounge for food over here, then vocal challenges are followed up with frantic flight and chase scenes.
Occasionally, disputes break out when different species that share a similar habitat encounter each other. This is evident in the waterfowl world, where ducks, geese and swans have shared needs but the timing of those needs are staggered. Canada geese arrive very early in the season, already paired, and set up a nesting zone, often fighting with another pair as to who gets to claim the muskrat lodge as a nest platform.
After a bit of squabbling over who gets what, a treaty is agreed upon and each pair of geese goes about the business of egg laying and incubation. Interestingly, at least with geese, is that as soon as the goslings hatch, all boundaries are dissolved and a communal daycare is set up. Goose neighbours, once Hell-bent on displacing the other, now share the looking after of the blended flock of yellow floating fuzz balls.
By this time, however, swans have returned to the wetlands, and swans are very aggressive at maintaining what they consider is “theirs.” They nest a bit later in the season, and will patrol their boundary with great determination. Trespassers are not tolerated.
The following scene played out before me last week as an extended family of Canada geese swan serenely by, led by an adult, followed by 34 recently hatched goslings and a second adult bringing up the rear. Aww. Great photos.
In the background was a trumpeter swan, a very alert bird, and he was not happy with these geese merrily swimming through his territory. When swans try to get airborne, they run across the surface of the water with great slapping sounds as their huge feet hit the surface and propel them onwards.
“Slap-slap-slap-slap-slap” came the rushing sound of an approaching swan, but rather than gaining height it was just gaining momentum! SLAM! He did a broadside hit to the lead goose, rolling it over onto its back. SMACK! A large swan foot drives two goslings underwater. Water flies everywhere.
There is a slight reprieve and then the swan attacks again, this time pummeling the other goose which had been trying to round up the frightened youngsters. More wing flapping, water flying and desperate honking. The swan backs off a bit and the geese make for the shelter of the nearby cattails.
“Slap-slap-slap-slap” as the swan again charges, this time targeting the lone goose still in the open water. It is close, but the goose eludes the swan’s wrath. A moment of silence as the swan rears up and flaps its mighty wings, then it paddles away to patrol other sections of the marsh.
Territories are essential for the successful rearing of young. As habitat of any description is removed, altered or outright destroyed, it severely reduces that element of “space” from within the habitat. Without enough space to find food, water and shelter there is overcrowding as the birds fight to control the little bit that remains. And the constant strain of trying to hold the line becomes detrimental to the health and success of that species.
So, while we may enjoy the cheery whistles of orioles, cardinals or rose-breasted grosbeaks, it is anything but peaceful within the bird world of boundary placements.
Dave’s Notebook: When the weather takes us from wearing a toque to wearing a sun hat in less than a week, perhaps all we can do is embrace the diversity of our climate.
© 2021 David J. Hawke