On banding birds

Yellow-bellied Sapsucker

Yellow-bellied Sapsucker

Yesterday I started a new job, running the spring migration monitoring program for Innis Point Bird Observatory on the Ottawa River. It’s a short-term contract, running until June (the length of the spring migration, unsurprisingly), but during that period I’ll be out there six days a week. Even after just two days, I’m quickly realizing that my available time is going to be considerably more limited than it was before, and I’m going to have trouble keeping up with everything, at least as I do it now. So, at least for the time being, I’ll be scaling back my blog posts a bit; instead of doing the occasional “Tay Meadows Tidbit”, they’ll all be tidbits, and I’ll do away with the title (which would just get repetitive). Now let’s just hope I can keep my rambly fingers in check!

Common Grackle

Common Grackle

The focus of the migration monitoring program is to monitor birds, of course. It’s a bird banding program, where birds are captured using standardized methodology that allows for comparison of results over many years. Data is collected for each bird caught, including age and sex, weight and fat levels. The former two measurements tell us something about the demographics of the population, which can be useful in detecting and assessing population trends. For instance, if a particular species starts showing a lower-than-normal proportion of young birds in the captured sample, it’s a suggestion that they’re having trouble reproducing successfully, perhaps due to poor breeding seasons because of weather conditions, or because of environmental problems that are causing increased chick mortality. The latter two measurements (weight and fat) are used in assessing the health of the birds arriving at the station. Low weights and fat levels are generally an indication of a bird that’s just arrived from a long flight, but if it doesn’t bulk up quickly in preparation of its next leg (which is detectable through recaptures of the birds again before they leave the site to carry on) then it could be the bird is in poor health, or it’s having trouble finding food. Over and above all that, though, is simply a documentation of the numbers of each species banded. If you start to notice long term trends – for instance, you band fewer of a species now than you did ten years ago – it’s probably cause for concern. The migration monitoring is especially useful for bird species that nest in the boreal, north of what’s sampled by the Breeding Bird Survey, since it’s often the only reliable means of monitoring their populations.

Tree Swallow

Tree Swallow

Of course, each bird also gets fitted with a band that will identify where and when it was banded if it should ever be encountered again. Historically banding was used as a way to track migration routes and patterns, but fewer than one of every 1000 birds banded is ever seen again away from the site where it was banded. That’s pretty slim returns; you have to band a heck of a lot of birds to get even a small sample size. Still, hundreds of banders banding over several decades have built up a pretty good database of re-encounters, and these days we’ve got a decent idea of where birds go. The focus of banding has shifted to population monitoring, as explained above. The bands are still useful for this, though. A substantially higher percentage of birds are recaptured again between their first banding and when they leave the site to finish their migration. By recording their weight and fat levels again next time they’re encountered (for which you need a band in order to be able to identify individuals again) it’s possible to track how the birds are faring and how well the site fulfills its role as a stopover location.

Red-winged Blackbird

Red-winged Blackbird

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13 responses to “On banding birds

  1. Mind if I add a link to this post over at the “ifoundabandedbird” blog? It’s an eloquent picture of the “whys” of banding that I think would be beneficial =)

  2. Thanks for this very interesting and informative and I loved the pictures, especially the tree swallow!

  3. Absolutely beautiful pictures! The colours are so vibrant.

  4. I think I’ve talked to you about this before, but I forget the answer. If you catch a bird that already has a band, do you put another band on it? Is there a database somewhere where you can enter the band number of one you catch and you can see all the times it’s been caught and the locations?

    • No, a bird in its lifetime only ever gets the one silver, numbered band, unless that one is so old, and so worn, that the numbers are hard to read, in which case it’s removed and replaced. It only ever wears one at a time, though. Some projects will also put coloured plastic bands on them in addition to the silver ones, to make them easier to identify from a distance, but the stuff Dan and I do doesn’t use that.

      There is a database, yeah. You can send your info in to the Bird Banding Office in Ottawa and they’ll be able to tell you its capture history (there’s a website to do this, or an 800 number to call). If it’s one of your own birds, though, having returned, you’ll have the data on your own computer and can look it up when you get home.

  5. gorgeous gorgeous gorgeous pictures…love the red of the sapsucker and the blue on the tree swallow :)

  6. Spectacular photos! The red-winged blackbird is my special favorite. I’ve been in love with those birds since the third grade.

    More importantly, thank you for explaining how banding data are utilized. I report banded birds when I see them, but someone asked me recently how the data are used and I fumbled with a meager response because I didn’t know all the details. This post is precisely what I needed to know.

    • I’m surprised you’ve seen enough banded birds to have reported plural, Jason! I don’t think I’ve ever seen one outside our banding operations, except maybe a Canada Goose once or twice. Good on you for reporting them, though. Glad the explanation was useful!

  7. Sounds like a really nice job! I am sure you are making many pleasant encounters. Please take more of those beautiful pictures!

  8. Thanks, everyone, for your comments! I’ve been absolutely dreadful about replying to them recently, having suddenly lost 10 hours of my day to the job detailed above, but I do really appreciate getting them all.

  9. People in stores make cotemnms like you’ve got your hands full when I go with my small family of two kids. I don’t make anything of it, they’re just making conversation. I am so impressed by you cool mamas of many. What a cute family!

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