Thursday, January 18, 2018

Another Take on Snowy Owl (Harfang des neiges) Movements

     The other day, while killing a little time on a visit to Windsor, ON Miriam and I dropped into a bookstore (isn't that what every sane person does?) and I picked up a copy of The Thing with Feathers by Noah Strycker. It is filled with chapters about different birds with a multifaceted examination of their behaviour (part of the subtitle for the book is The Surprising Lives of Birds)and, about a third of the way into it, I have found it both entertaining and informative.
     I was especially struck by a chapter called Snow Flurries about Snowy Owl (Bubo scandiacus) behaviour and its relevance to the area in which I live, where this magnificent denizen of the arctic tundra is a regular winter visitor, sometimes in substantial numbers.



     It confounds some of my friends that we are able to see this species with such ease, and I suspect it causes not a little unseemly drooling!



     Conventional wisdom has often advanced the notion that movement into the south (south for the bird that is) has been triggered by a shortage of food in the arctic, especially in irruption years, when the presence of large numbers of owls has been attributed to crashes in the Brown Lemming (Lemmus sibiricus) population. See the following references:

North American Owls, Paul A. Johnsgard (1998):  ....incursions......generally occur at intervals of about 3 - 5 years, coincidentally with cyclic or periodic declines in lemming populations.

Owls of the World, Edited by John A. Burton (1973): It is a decline in the availability of prey, ......that is a cause of Snowy Owl irruptions.

The Owls of North America, Allan W. Eckert (1987): Migration is extremely cyclic and predicated on the availability or nonavailability of prey.

Owls, Tony Angell (1974): The migrations are stimulated by the shortage of their principal foods, lemmings and Snowshoe Hares.

     The diet of Snowy Owls, however, is varied and includes other rodents, ptarmigans, songbirds and waterfowl. In the winter in southerly locations a Snowy Owl is very opportunistic and will take whatever prey is readily available. This female is eating a Mallard (Anas platyrynchos) in Bronte Harbour, Oakville, Ontario. For birds that regularly winter at this location, waterfowl forms the principal items on the Snowy Owl menu.



     Snowy Owls are nothing if not peripatetic and have a highly nomadic lifestyle. Strycker cites the example of seven chicks banded on Victoria Island in northern Canada, three of which were subsequently relocated at Attawapiskat, Ontario (2,050 km), Clyde Forks, Ontario (3,250 km) and Sakhalin, Russia (5,300 km). These movements are seemingly unrelated to seasonal food shortages and reflect the inherent behaviour of an avian nomad. In fact Snowy Owls seem to manifest little or no inclination to site fidelity at all.
     To return to the question of whether precipitous declines in lemming populations are the reason for mass Snowy Owl movements to the south, it appears that exactly the opposite is true, borne out as Strycker points out, by rigorous statistical analysis of both the biomass of lemming prey and the movement of owls.
     All the evidence points to Snowy Owls having a highly successful breeding season in years of lemming abundance, rearing seven or eight chicks in an average nest, a prodigious feat indeed. When these young birds fledge, there are not enough territories to go around and this is what triggers a mass migration south, and results in the spectacular invasion years we sometimes see in southern Ontario, where in an exceptional year it is possible to count twenty-five Snowy Owls in less than a forty-five minute drive from my front door.
     So, it is a bonanza year for lemmings that stimulates mass migration from the tundra, not the opposite.
     There is support for this assertion in the literature:

Owls of the World, Rob Hume (1997): When the population reaches a peak after a good breeding season, more owls will move south, especially young birds working hard to survive their first winter.

Owls of North America and the Caribbean, Scott Weidensaul (2015): Although most people assume that hunger drives irrupting owls south, in major Snowy Owl invasions the cause is usually extraordinary plenty, not privation.

     I would like to end this short piece with a plea to my fellow birders, and especially those who in recent years are far more likely to carry a camera with a huge lens. Please, do not trespass on farmers' fields to get closer to the owl. This causes problems for others, especially those of us who have working relationships with farmers who permit us to study birds on their property, causing them to become resentful of the birding community and withdrawing our privileges. Furthermore the owls are resting between bouts of hunting, and disturbing them so that you can get the perfect flight shot causes them to expend valuable energy unnecessarily.
    The same admonitions apply to birds found in harbours. Do not try to gain access to private docks where you have no business trespassing. Think of the whole picture and not just your desire for a better image.



      Enjoy the bird at a respectful distance and consider yourself one of the lucky few able to spend time with this iconic bird of prey.
David M. Gascoigne,
David M. Gascoigne,

I'm a life long birder. My interests are birds, nature, reading, books, outdoors, travel, food and wine.

51 comments:

  1. I would love to see the Snowy Owl, you are so magnificent to get one, lucky lucky.

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  2. Hari OM
    I am one of those drooling at your good fortune in obtaining such shots! It is such a stunning bird. YAM xx

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  3. How beautiful! They can be here in Norway too, but very seldom. Very nice shots.
    I have a Sparrow Hawk here where I live, but it's very difficult to take good photos of it.

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    1. Yes, birds of prey can be very difficult to photograph, Marit.

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  4. Hello, Great post on the Snowy Owl. There are a few of them being seen in Maryland and Delaware now, I have to get out there and see them. Beautiful owls and photos. Enjoy and have a happy day!

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  5. An interisting an nice article to read and nice photo's too. We had (a) Snowy owl(s) in The Netherlands but only in the North on the 'wadden'islands. I didn't went there but many twitschers did.
    I very much agree with your last paragraph, this problem seems to become bigger and bigger. There are imho over the last year more photographers and less birdwatchers
    . And although there are nice and polite photographers ther are also the not so nice guys that will do everthing to get the picture. As we say: the bigger the lens, the closer they get :-S.

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    1. Hi Marianne: It's true what you say. The people with the biggest lenses seem to need to approach most closely. You would think it would be exactly the opposite.

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  6. this one I would have loved to see for myself. It is such a beautiful bird. Great shots.

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  7. Wow, what a nice capture. Owls are my favorite bird.

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  8. I would give my gold tooth to see one of these guys. I noticed in Texas many photographers who elbowed birders out of the way so they could get shots Im in favor of get your shot then move on so everyone can get a look and shot.

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  9. They do look a beautiful bird, have never seen one only in photos.

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  10. Hello David!
    Magnificent shots of the Snow Owl!
    Wonderful pictures!
    Snowy Owl is my favorite bird!
    I really enjoyed your post!
    Have a lovely weekend!
    Dimi...

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  11. Hi David.

    Beautifully this Snowy Owl.
    Nice that you could put it on the photo.

    Groettie from Patricia.

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  12. A very interesting post, David, which had me having to break off part-way though reading it to don the pelican bib in order to protect my shirt.

    I hope that I am one of the more considerate photographers - I certainly do my best to be. However, I do find that there are a number of selfish photographers out there who give little consideration to other people or to the welfare of their subject matter, and giving photographers in general a bad name. It is a problem in the birding community, but not unique to photography. Sadly, there are also some birders out there who, in spite of carrying powerful 'scopes, seem to find it necessary to see how close they can approach a rare bird.

    With love to you and Miriam - - - Richard

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    1. Based on personal experience, Richard, I can vouch that you are among the most considerate of photographers. I never saw you do anything that made me wince. Now were I to see you drooling into that pelican bib, that would be a different story! Much love to you and the missus!

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  13. Hello David,:) Loved this informative post. You are lucky to see the Snowy Owl in the wild. I can only see these beautiful birds in a nature reserve. Enjoy your weekend!:)

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  14. This snowy owl is beautiful. You are so fortunate to get to see it. Such a rare bird!

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  15. This is a really thoughtful article. I recall, when the irruption first began, they began telling us it was due to an abundance of lemmings. This year, I think the bird lobby groups are milking the shortage of food and foretelling a shortage of Snowies for attention and funding purposes. (But I am a cynic, and avid politico!)
    Regarding squirrels, trapping and moving them won't do anything. You'll add to someone's woes, break up a family (perhaps), and, as you say, more will simply move in.
    This is what the MNR does for raccoons and rabies: trap them and inoculate them, as more will simply move in. They have compensatory reproduction, as well.
    Anyway, great post.

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  16. A great read David and how lucky to have such beautiful birds on your doorstep! Unfortunately we have issues with 'birders (photographers)' going where they shouldn't here in the UK too, it's quite disheartening.

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  17. Another gorgeous post, David. What a handsome bird!

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  18. I would never go onto someone else's property to take photos without asking first. I would never expect anyone to walk on to our property without asking. I am stunned that people actually have the cheek to do that. Think that is why I have never got any photos of the Little Owls which are in out area, they are always just out if reach!
    Great photos. Have a good weekend Diane

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  19. Wonderful photographs. I have never seen this type of owl. I love their coloring. I hear they do hang out in areas of Montana. Perhaps it is time for a long drive to see if I can see one.

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    1. Hi Tammie: Montana certainly is climatically suitable, but they like large flat expanses and I always think of Montana being very mountainous.

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  20. Hi David,
    Superb images of such a delightful bird, obviously a bird I have never seen but very envious of those that do.
    Also a very interesting script on the habits of the bird and my they certainly range over an enormous area, makes our Barn Owls appear to be day trippers!!!
    Most enjoyable post.
    All the best to you both, John

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  21. Hi David,just had to say what a fantastic post,outstanding images,I had to pick up my Jaw up off the floor when I clapped eyes on the Snowy Owl shots,I've now stopped drooling.
    I also enjoyed reading your report,great write up.
    If we are lucky we might come across one or two in Cornwall,there was one reported about three weeks ago,which I missed.
    John.

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  22. It is said about owls that they are wise birds and that's the truth. They move where it is easier to get food. It's a beautiful bird and I probably will not see it alone. * I am very happy that you are my regular guest. Regards.

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  23. They are certainly beautiful. I enjoyed reading the information you provided. Plus, I agree about not trespassing to get a better shot. Good advice.

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  24. That's very good advice. We need to be respectful of our surroundings even in the wild. This is a beautiful owl and you photos are superb. We hiked the Florida Trails today and I was hoping to see an owl....but no luck. I did have a ladybug land on me though and that's supposed to be good luck.

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  25. Nice photos. Interesting research on the snowys because it now makes sense that many of the ones I've seen in Minnesota in the winter are juveniles. One of my favorite birds. I used to drive all over Northern Minnesota to see one when it had been spotted. Minnesota birders are the most considerate ever but I'm not finding that in South Carolina where I now live.
    I was wondering if you would consider putting a "follow by email" box in your sidebar. It would be nice to be notified when you have a new post.

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    1. Let me see if I can do that Cynthia. Sorry to hear the the birders in your new state are not as friendly as the one you left behind in Minnesota.

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    2. If you follow my blog, Cynthia, each post will show up in your reading list.

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  26. You are very fortunate, indeed, to see such beautiful creatures not just in books and on blogs. I’ve never realized until now that a snowy owl can look a bit like a baby seal from certain perspectives. I’m looking at your third photo down. Very sweet!

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    1. You are right that I am fortunate. I see them every year but I never lose my sense of awe; if anything it is magnified each year. It is going to be a challenge for this cold-adapted species to cope with a warming climate - especially when the permafrost starts to melt. What that will do to the lemming population is probably not hard to predict and the consequences will be dire for many species who depend on them.

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  27. I’m awed and envious. Thank you for this .

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  28. Hi David. I am doing my best to catch up with everyone after a week and more off due to being somewhat lazy and that dreaded word "weather".

    How I envy you those dry, but sunny if cold days, in place of our continued wet and wind and dispiriting starts to a morning. Your post today is most illuminating with many fine pictures. Like many, I have seen the magnificent Snowy Owl only in captivity with I recall, one especially angry individual crashing against the confines of its cage when anyone ventured too close.

    I hope that your final paras do not fall on deaf ears but suspect they mostly will. As you know, we have a similar problem here multiplied x10 or more.

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    1. You are so right, clear and cold is much preferable to rain and gloomy conditions. We have that kind of day today as a matter of fact. We are meeting friends out for dinner tonight so I hope all the water doesn't freeze.

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  29. http://www.greenwichtime.com/local/article/Local-Facebook-birding-group-bans-owl-photos-12512381.php

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    1. It's a step in the right direction to be sure, but I doubt whether this will deter unscrupulous photographers who have countless other opportunities to publish their images, including on their own blogs such as this one.

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  30. Beautiful pictures. I remember my daughter took a picture of the snowy owl a few years ago when it was spotted in downtown DC .

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  31. Superb photos. Awesome bird. Greetings.

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  32. Such a lovely informative post on the Snowy Owl, loved seeing the photographs.

    All the best Jan

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  33. Hello David, this is such a magnificant bird. Great captures!
    Regards,
    Roos

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  34. Oh my God, this is so a beautiful bird !! It would be great to see and photograph a snowy owl! Wow ! Gorgeous photos !!
    Happy Sunday !!

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  35. Great photos....Thanks for the informative posting. It's a pity some photographers are so selfish, but it's a worldwide thing these days !

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