When one thinks of winter in central and northern Alberta, it is rare that the first thing that comes to mind is colour or in imagining too many things surviving without being wrapped in fur or goose down. When I close my eyes to imagine Alberta in winter, I generally envision serene beauty in massive expanses of shades of white and brilliant blue skies, with fluffy white clouds. It is hard to imagine anything that appears as delicate and vulnerable as a bird being able to withstand the crisp cold days and even colder nights.
Yet they do... and not just survive, they thrive. Regularly spotted are flocks of colour that spritely bob and weave in united, fluid choreographies and formations. Often you can be standing looking at a tree and see it seemingly lift into flight as the hundreds that were perched inside decide they suddenly need to be somewhere else, operating as if with one brain (called murmuring).
With all of that monochrome happening, it is with a display of both practicality and whimsy that nature imbues the landscape with beautiful shades of colour, as the ultimate in accents. Whereas the animal world in Alberta is generally of the colour that aids in their camouflage, birds often are gifted with colours, hues and patterns that can surprise and often delight. My parents have described their bird feeders recently as appearing like lovely Christmas trees, festooned with multi-coloured ornaments.
In order to restore all that energy spent just to stay alive, species of birds are eager to feast not just on the generous feeders put out by caring birders but also on berries and seeds that nature herself has made available. And eat they do.... my father recently recalled how he had to wash all of his vehicles as they were covered in skat (droppings) and how the patio deck was covered in the red dots from the mountain ash berries consumed by those “Swarms of Shitters” as he calls them (always with a chuckle and a twinkle in his eye).
One of the interesting species of birds observed in northern Alberta are the colourful Red Crossbills, along with their cousins the White Winged Crossbills. Now one of the most interesting thing about these birds is how they get their name and what that tells us about nature as the greatest equalizer. The bills of the crossbill start out straight and then begin to cross as the bird matures and have fledged (gotten their adult feathers and are able to gain their independence and fly). Fascinating about the Crossbills is that there is an approximate 1:1 ratio of instances where the the bill (which has two parts - the lower mandible and the upper mandible) cross to different sides. It is not truly understood if this morphing is the result of genetics or environmental selection. Evidence so far is it is a combination of both.
In Red Crossbills, half of the population has the lower mandible curving to the right and half has it curving to the left. It is similar to human handedness, but the ratios are equal in crossbills. (As a left-handed person I find this even more fascinating as left-handedness occurs with less frequency in humans - approximately 9 right-handed people for every 1 left-handed one).
It is interesting that the population who feed on cones without requiring to remove them through twisting will still likely show a 1:1 morph distribution, no matter what the genetic basis may be. The fitness of each morph (i.e. its likelihood of occurring in the next generation(s)) is inversely proportional to its frequency in the population. That is, nature equalizes the numbers so that there isn’t an increased chance of being too many birds at one time that access the seeds through one dominant mandible over the other.
The bills cross to different sides because when feeding on a cone from a perch, they have to turn their head in a particular direction so that the lower mandible is on the bottom. This makes it easier for them to reach certain seeds, while other seeds aren't worth the time it would take to reach them.
If a right-beaked bird comes across a cone that a left-beaked bird already foraged on, they will find seeds left which the first bird couldn't reach. In contrast, if the right-beaked bird came across a cone that another right-beaked bird has foraged on, there will be slim pickings and not much in the way of leftovers and evens out the possibility of survival for each of the types of the crossed beaks.
To put it another way, Crossbills are able to utilize other conifers to their preferred, just like we can eat foods other than our favourites, if our favourites are not available. Often they need to do so when their preferred species has a crop failure, although they are less efficient in their feeding (not enough to prevent survival but probably enough to reduce breeding success... it always comes back to love!) Different species of Crossbills have different preferred food sources, which is why there are 8 or 9 discrete populations of Red Crossbill in North America alone. Predominantly they do not interbreed and each are adapted to specializing in different conifer species. For example in Alberta, Red Crossbills (often referred to as Common Crossbills) prefer Spruce, Pine and Douglas Fir while the White Winged Crossbills love Larch and Hemlock.
The Crossbill is just one more demonstration of how nature is constantly coming up with ways to awe. It never ceases to amaze me how there is yin wherever there is yang. Whenever anyone talks to me about the desolation and harshness of an Alberta winter, I remember that just as there are many different kinds of birds so there are varieties and variations on the beauties of life. I adore that winter (and spring, summer and fall) in Alberta is full of birds that help us to sing along to this different tune.