Tuesday, January 24, 2023

 

 


Curious Species

Fundamental to avian science, birders help protect our planet

 By Peter McKenzie-Brown

If you live in southern Canada, from the Atlantic provinces to the Rocky Mountains, you have likely seen a Ruby-throated Hummingbird. Beautiful but solitary, these tiny birds breed in the north of the continent. But think about what they do during migration.

    In fall, they fly south through the US. Most end their journeys when they reach the Gulf of Mexico, but not all. Almost incredibly, they fly across the Gulf of Mexico to the Yucatan Peninsula – an 800 km, non-stop flight that would seem to require more calories than their three-gram body weight could provide. Though born in this country, they make instinctive beelines to their winter homes. They may even return to the same gardens – both in Canada and around the Gulf – year after year. We know that because bands on their tiny legs enable us to track their passage. This story is about those bands.

    I’ve been a birder for years. The hobby lures me into the natural world to watch species often of extraordinary beauty and splendid song. The friend who got me into birding, Dave Russum, tells me he has observed 250 species within Calgary’s city limits in a single year, and knows someone who has seen 293.

    The birders I know worry deeply about species loss – a concern superbly explained by the Wilder Institute, which is associated with the Calgary Zoo. The institute explains with chilling effect the dangers species face around the world. Vast numbers of avian and mammalian species are at risk.

    Dramatic reductions in the populations of bird species because of changes in predation, farming, and forestry practices are the backstory to our efforts. In Alberta, bird-loss led to the development of “Bluebird trails.” These trails consist of volunteer-built nest-boxes placed at intervals along highways and byways to provide safe breeding sites for the Bluebirds.

    Opportunistic Tree Swallows face less environmental risk, but like the boxes. The result? On our Mountain Bluebird Trail we mostly band Tree Swallows. For both species we record nesting successes, numbers of nestlings banded, age and gender of the chicks. When we capture adults, we band them, too. In autumn, we band Northern Saw-whet Owls migrating from the boreal forest. To band this species, we set up mist nets in the woods nearby.

    For the record, mist nets date back to 17th century Japan, according to an article in a 1982 issue of the North American Bird Bander. The technique arrived in North America after WWII, after which birders around the world began using them as a critical banding tool. We blare into the sky the recorded voices of these diminutive owls. Small numbers (perhaps six) fly into our tiny mist net and become entangled. We carefully disentangle them, band their legs, do various biometrics, and set them free.

    Our efforts are a miniscule part of a global effort to understand and assist our avian friends. We attach bands on the young birds’ legs just before they leave their nest-box. If anyone recaptures a banded bird, or finds a band on the leg of a dead bird, that band provides information on how to report the date and place. This information helps the ornithological community better understand migration patterns and changes in behaviour over well-defined periods.

    Known as “ringing” in the UK, banding is a logical continuation of birding. Taken together, they contribute to the simple realities that most people need nature to be happy, and that little in nature is lovelier than birds and birdsong in the wild. Banding practices around the world help our avian friends, but only because of the vast international machine in which each bander is a miniscule cog.

The Early Years In North America, John James Audubon and Ernest Thompson Seton were pioneers in bird tracking, although their method was primitive compared to banding as we know it today. To determine whether the same bird would return to his farm, Audubon tied silver threads onto the legs of young Eastern Phoebes in 1805. He soon became a committed birder – later publishing the New World’s most famous bird book, The Birds of America.          

    Seton may have become the first marker in Canada nearly three quarters of a century later, when he used ink to mark Snow Buntings on his Manitoba farm. Like Audubon, he wanted to see whether the same birds would return the following year.

    Banding as we know it today began in 1899, when Danish schoolteacher Hans Christian Cornelius Mortensen started using aluminum rings on European starlings. Within two decades, banding had spread across western Europe and much of North America. Federal programs began in the U.S. (1920) and Canada (1923) in response to the 1918 Migratory Bird Treaty agreed between the two countries. To a degree, this treaty reflected the then-recent extinction of the Passenger Pigeon. Indigenous to this continent, these tasty and easy-to-hunt birds numbered perhaps seven billion when Europeans arrived. By 1900, they were virtually extinct. In 1914 Martha, the last of her species, died in the Cincinnati Zoo.

    Long-term, continual records of the bird-banding community are vital to understanding changes in population and species movement in a rapidly changing world.

    Banders maintain the boxes to keep records of nesting successes and failures. Licensed banders clip a band on one leg of captured adults and mature nestlings. When we recapture banded birds, our reports to ornithological authorities help avian science gain a better understanding of the migration patterns, ages, and changes in species behaviour over a well-defined period. The bands themselves neither harm nor hamper the birds.

    With the help of banding armies, ornithologists long ago established that migratory birds are at risk, and need intact habitats to survive. A few years ago, the Audubon Society (named after the renowned birder) published Survival by Degrees, a report showing that 64 per cent (389) of North American bird species risk extinction from climate change, industrial development and other factors. This gloomy report argues that only immediate, determined action could improve odds for three quarters of those species.

How does banding protect birds? As banders do their work, they record the location, date, species, gender, estimated age, and other features of the birds they band, and send that information to the lab. To ensure the birds’ well-being, trained volunteers and researchers undertake the capture and banding. The United States Geological Survey (USGS) works with The North American Banding Council, which develops banding materials and addresses safety issues.

    Those who catch a banded bird or find its corpse can report its banding information back to the lab, which keeps records of such encounters. USGS staffers manage more than 77 million archived banding records and another five million bird-encounter reports. The organization processes some 1.2 million banding records and 100,000 encounter reports each year.

    Through banding research, scientists can learn a bird’s routines – where it spends most of the day, its migration patterns, what it eats and how much habitat it needs to feed and reproduce. This information helps identify priority areas for conservation. For example, changes in the age of birds caught at a certain location may indicate longer or shorter life expectancy. The number of captures may indicate whether populations are increasing or in decline. Data such as weight and wingspan can show health trends. Such insight can cue scientists to look for changes to birds’ food sources, predators, competitors, habitats, and other factors that affect their survival and reproduction. Sampling wild birds for Lyme Disease and Avian Influenza can help determine these diseases’ prevalence. Bird migration routes can identify which human and animal communities are at risk of exposure too. And toxicologists can determine effects of avian exposure to contaminants and other environmental threats.

    Banding is by no means new. In 2020, the USGS published a celebratory article about banding’s first century in North America. Birders are among the multitudes aware that most birds bring joy merely by their presence – from their bold colours and majestic songs to their grace as they flap or glide through the sky. But they contribute more than beauty. Many plants depend on hummingbirds and other species to pollinate them. Hawks and owls target rodents and other pests. Fruit- and grain-eating birds help spread the seeds of the plants they consume.

    Different types of markers are used depending on the type of bird, its behaviour and the information needed. Bands are small and light to avoid impeding movement. Banders follow strict protocols to virtually eliminate harm or hindrance to the species carrying them.

    Banders clip a small metal band with a unique number on the bird’s leg so that when its band is reported its movements can be reconstructed. Birds may carry other markers. These include neck collars for geese and swans, which are readable from a distance with binoculars and spotting scopes. Wing markers on vultures, eagles, swans, ravens, crows, or herons are often visible while the birds are in flight or perched. Leg flags on shorebirds stick out from the upper leg with a code which can be read from a distance.

    As a scientific technique, banding requires expertise and skill usually gained from years of study and field experience. To participate in banding activities, you must apply for a permit. Most of those with banding permits are professional ornithologists, biologists, and wildlife technicians. The others are keen birders who just want to help.

    The Canadian Bird Banding Office in Ottawa issues permits to capture and band within Canada.. Cooperatively run by Canada’s banding office and the American Bird Banding Laboratory, this program relies on the public to report sightings or recoveries of bird bands and other avian markers. In Canada, the procedures for reporting bird bands are quite clear.

    Banding data help scientists and researchers understand, monitor and conserve migratory birds. The presence or absence of birds in nature can indicate stressors affecting the ecosystem. Put another way, banding and its related technologies are now among ornithology’s vital tools.

    Like humankind everywhere, banders are curious about the world around us. People study everything on this planet – from subatomic particles to the tiniest microbe to the make-up of the cosmos in which our solar system is barely a speck. We are, after all, a curious species. 

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