Irruption

Redpoll at a log cabin feeding station

A wave of tiny birds erupts at our bird feeders. They supplant the normal visitors, chickadees, goldfinches, pee wees, nuthatches, and cardinals. By sheer numbers they overwhelm both the other customers of this dietary dispensary and the supply of food within the feeders. In a matter of hours they empty six feeders, each holding a half of gallon of black sunflower seeds.

This invasion of redpolls is not unprecedented. It last occurred about five or six years ago. Like then, the available food in the boreal forest and tundra five to eight hundred miles to the north is inadequate. These many birds, which seem to act like one in a manner similar to honey bees, have vanquished the far north in search of reasonable food supplies. We seldom see a bird or two, rather they arrive in flocks of several hundred birds about twice a day. They gorge for about twenty minutes before retiring to the nearby forest. They always arrive and leave in a massive flock. It’s not like one or two scout birds arrive and go back to tell the others. No, there entrance is a flood of birds. They arrive in one wave, nearly empty all of the feeders, and exit like the same wave retreating from the beach.

Redpolls competing for food at a feeder.

Redpolls feed primarily on seeds in the cooler seasons. There favorite food appears to be white and gray birch seeds, poplar seeds, willowm and alder seeds. They also dine on tamarck seeds. The far north is chuck full of these tree and shrub species. These deciduous plants are uniquely adapted to the northern climates. The tree’s shrub’s entire identity is dominated by evolutionary tricks that allow them to live in these severely cold climates. Some might consider them the Nanooks of the plant kingdom. But every once in a while climatic conditions limit seed production. Unexpected cold during their flowering period, drought, and severe storms can all limit their progeny. This past summer must have held one of these events. There is little viable seed in the boreal and tundra deciduous plant community. And the birds have left for greener pastures, so to speak.

These mass exoduses are known as irruptions (no, not eruptions). Redpolls are not the only birds to leave in large flocks. Pine siskins, purple finches, white winged crossbills, and pine grosbeaks will do the same. These bird species are highly dependent, during the winter months, on these massive seed supplies that are usually plentiful in the far north. Like all foraging it is a matter of locating and gathering sustenance for energy. Without the sustenance to keep them warm the red polls would perish in the extreme climates of the boreal forest and tundra.

This chickadee waits for a space at the feeder before joining the redpolls for dinner.

Redpolls are unique amongst the finch family. Their tiny size allows them to subsist on a frugal diet. They rely on large flocks to survive. The “many eyes” of a flock helps them to locate each and every food source within a given area. The flock seems to operate as one organism. Red polls also are well adapted to cold climates. Like many small birds they can ruffle their feathers to trap air and insulate their tiny bodies. In extreme cold they will dive into the snow. There the temperature can stay just at or slightly below freezing when the air temperature is well south of thirty below zero (Fahrenheit).

Perhaps the most unique adaptation that the red polls possess is their esophageal diverticulum. This unusual feature is a small pocket situated in their neck. Redpolls use the esophageal diverticulum to store seeds. By having a food supply “to go” during a storm or an extreme cold period they can have a ready supply of energy while sheltered from inclement weather. .They regurgitate the seed when ready to consume them allowing them extended consumption without an expenditure of energy. Energy conservation is the most important aspect of survival in extreme climates. Without energy conservation many of these species would perish.

Interestingly, redpolls are not aggressive. When they invade a feeding station or feeding location they do not chase other bird species away. Both blackcapped chickadees and goldfinches seem tolerant of these mass entrances although some shy individuals may exit temporarily. They feed amongst the many redpolls, competing for food the best they can. They seem to know that the redpolls won’t stay long. After gorging for twenty minutes or so the redpolls all leave at once when they fly off to some not too far off tree where they seem to enjoy each others company.

Redpolls!

Redpolls are best identified by the small red cap on the top of their heads. The males often have a reddish wash of colors on their chest as well. They are about the size of a chickadee and nearly always in a large flock. During the summer months they enjoy the long days of the far north. During the warmer season they consume part of the large flying insect population; a seemingly never ending food supply in these northern latitude environs!

As I watch these little critters eat enormous amounts of bird food at our feeders I feel a sense of wonder. That they are just outside of my window is marvelous. That they choose to visit our bird feeders is just reward for our bird feeding habit.

And when they leave to head back north they will do so just as suddenly as they came. One day they will be here and the next day they will not.

I’ll envy their trip to the boreal northern sections of Canada. I won’t be taking mine until summer.

Black Capped Chickadee-Our Official State Bird

Written for www.wildramblings.com in January of 2013.

  • Barbara

    I Just LOVE redpolls – they arrived sometime in November I think, disappeared and have now returned since we have abundant snow. They’re cheeky, pretty and here are members of the gang of little birds that most often maraud my feeders… that they come to you in hordes and decimate your gallons of seed makes me both jealous of the numbers and sort of glad – I doubt I could keep up with that – as you know I’m having a hard enough time with the five then seven and today nine wild turkeys that have discovered the multitude of corn and other seeds under my feeders…

    What a great story and thanks for all the wonderful information. I had no idea what their preferred diet is, nor that they flock-and-fly as one, nor the habit of hiding in the snow to stay warm for Pete’s sake! Nature is always full of surprises isn’t it Bill. Thoroughly enjoyed this essay… I could almost hear those little wings move as one to a nearby tree – great writing.

  • http://www.wildramblings.com Wild_Bill

    You are so flattering Barbara. Thank you for your wonderful compliments. Glad you enjoyed this piece!

  • http://www.facebook.com/sue.sweeney Sue Sweeney

    Very interesting…. could be some major ecological disruption at work when the red polls and the like eat and carry off local seeds that otherwise would have ended up sprouting under local bird roosts. YOu have any thoughts on how that all plays out?

  • http://www.wildramblings.com Wild_Bill

    Yes, it would not likely occur. Given the entire evolutionary concept is energy conservation it is unlikely the redpolls would fly any great distance before consuming seeds. They stay close to foood sources and only utilize the food storage system in extreme weather. Also, the ecological world is a mosaic of many different phenomenons. It is totally capable of accepting and adjusting to naturally occurring events. Redpolls and other birds have been irrupting for thousands of years so this is nothing the overall ecological system has been exposed to. I worry more about climate change and what that will do to our plant and animal species.

  • Montucky

    That’s a great shot of the Chickadee, which is my favorite bird! What in the world would we and the birds do without black sunflower seeds!

  • http://www.wildramblings.com Wild_Bill

    One of my favorite birds too! I’m a huge black sunflower seed guy. I’ve tried lots of different types of bird food and this is one of the few that gets consumed readily with very little waste!

  • shoreacres

    I’ve neither seen nor heard of a red poll until just now! Their flocking behavior is so interesting, as is their adaptation to the cold. I have to keep reminding myself that many of the birds I see – and feel so sorry for during inclement weather – are well adapted, and know precisely what to do to ensure their survival.

    Because I live in an apartment, my options for feeding are limited by my downstairs neighbors’ tolerance and the rules against seed-over-the-side-of-the-balcony. But I have found that raw shelled peanuts, chopped up pecans and shelled sunflower seed, while a little expensive, will meet the requirements quite well. I have bluejays, some sparrows, doves and pigeons, all of whom enjoy the food. Everything else in the neighborhood is a water bird – herons, gulls, mallards, coots, egrets, ibis and spoonbill. They can fend quite well for themselves. I certainly won’t be flipping fish to them!

    How nice that the chickadee is your state bird! It’s such a delightful little thing, and your photo is marvelous!

  • http://www.wildramblings.com Wild_Bill

    It sounds like you have a good variety of birds to feed and they do, indeed, eat like royalty with that seed mix. Birds of all kinds are well adapted to fend for themselves, no doubt. Our human habit of feeding them is certainly helpful but not absolutely critical most years. I think of it as educational. I get to watch them up close and they get a little food. I’ve been trying for that shot of the black capped chickadee for some time and it just fell into place. Glad you liked it!

  • Teresa Evangeline

    One of my greatest joys in life is watching the goings-on at the bird feeder. It’s a front row seat to nature, and she always puts on a show. Wonderful things have happened there, from indigo buntings to ruffed grouse. Beautiful image of the chickadee

  • http://www.wildramblings.com Wild_Bill

    Yes, a front row seat! Lately it has been a squirrel fest, but they have to eat also! I haven’t seen an indigo bunting in a few years! I also like that photo of the black capped chickadee, just the right conditions when I took the photo!

  • Guy

    Hi Bill

    Our flocks are smaller in the city but I was posting photos of a flock of Crossbills and Redpolls on the spruce on my front yard yesterday, in Nov it was Crossbills and Nuthatches in the spruce by work. Crossbills seem to be very widespread this year.

    All the best.
    Guy

  • http://www.wildramblings.com Wild_Bill

    Just once I’d like to see a flock of Crossbills. Others in these parts have witnessed them but I haven’t! Please send me a link to your website!

  • Guy

    Hi Bill

    Here is the link to my website.

    http://thatsjustthewildwood.blogspot.ca/

    All the best
    Guy

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