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March 22, 2007  The Movement Of Birds In today’s title I mention bird movement. I’m not talking about the droppings which drip down the shiny paint job on your new car. I’m talking about the enviable mobility of birds. Earthbound humans have coined the term ‘free as a bird’ to suggest that birds are somehow above the fracas of life and if they do find something distasteful they just up and fly off. Perhaps it’s alright for humans to feel this way about birds; if we really knew of the shortness and perilous-ness of a bird’s life we would quickly lose one of our favourite inspirations. Even for those who see the existence of many natural bird hazards, (and our own species more unnatural contributions to a bird’s perils,) the mobility of birds is a great challenge to helping alleviate those hazards. For example, migrant songbirds must have a secure breeding ground in the north, a secure over-wintering area in the south and intact migration corridors connecting the two, and people must know a heck of a lot more about the birds’ movements if they are to be of any assistance. “Bird banding” as North Americans call it, or “bird ringing” as the British might say, is one of the most important methods used for tracking the movement of birds. I don’t have the figures to draw the following conclusion but I’d bet, for all the birds banded, less than 1% of the bands are ever recovered. This makes data gathering based on collecting bands a very slow process. It’s too bad birds don’t carry luggage so we could just read the tags and know where they’ve been, or better yet if birds could talk and would boast about their travels. Well, I’ve got good news. Due to recent developments in atomic analysis of hydrogen, birds have begun to talk. Not literally of course – it’s the bird’s feathers doing the talking. In the most recent issue of Birdwatch, a publication of Bird Studies Canada, an article describes a new way to track birds. In order to understand the article enough to explain it in my own words I read it four times. This is my understanding along with a suggestion that reading the actual article might be the best way to get to the heart of the matter. Two Canadian researchers, Dr. Keith Dobson and Len Wassenar, are credited with developing a technique for analyzing the hydrogen components in feathers. They found that two stable isotopes in the hydrogen component of water occur in different ratios depending on where the water originates. The feathers of birds that consume food or water from a particular area will contain hydrogen ‘signatures’ from that locale. To retrieve the necessary information all that is needed is a single tail feather. So far only rather general signatures have been identified but with further refinement in testing techniques, and further water analysis, it is expected that more detailed geographic details will be revealed. So far, through this analysis, it is possible to determine if a bird comes from a region the size of the Yukon, or the central Prairies, or Ontario, or Quebec. Another aspect of this research is that if a bird goes through a molt in the south the new feathers will carry the hydrogen relationship signature of the southern location. One could hardly imagine a better way to track creatures mobile as birds. And as methods of analysis become more stringent it may one day be as if every bird was banded so their information could be retrieved. Such a detailed trove of information about the movement of birds will certainly lead to a better understanding of flyway, nesting area and southern over-wintering site requirements and should point the way to better safeguard these components. Thankfully, this critical research and analysis will do nothing to infringe on the freedom of birds and thus we may continue to envy their carefree manners. To e-mail Tom CLICK HERE To look at previous column CLICK HERE |
