The decline in the population of swifts in the Banff area has prompted unique research methods to determine what the stealthy birds eat.
BANFF, ALTA — Desperate times call for desperate measures.
While little is known about the rare Common Swift, Parks Canada researchers are testing innovative ways to help protect this endangered species, including scouring droppings to find out exactly what these birds are eating.
“These guys are endangered, but they’re really, really enigmatic and difficult to study,” said Barb Johnston, the endangered species biologist who oversees the swift project in Banff National Park.
“We kind of think outside the box and use unusual techniques to try to shed some light on the basic biology of the species, because not much is known about them.”
A key nesting area for the endangered Common Swift is along the cliffs of Johnston Canyon, one of Banff National Park’s most-visited tourist hotspots, attracting hundreds of thousands of visitors each year.
Researchers use thermal cameras to locate and monitor nests, time-lapse remote cameras to reveal bird activity patterns, and temperature and humidity sensors to help understand the microclimatic needs of this species.
This summer, researchers will use meta-DNA barcoding of bird fecal remains to learn more about their diets.
“It’s diet analysis. We’re trying to find out what these guys are eating,” Johnston said.
“It’s a really unique opportunity to do some of this research because most of the sites where they nest are so inaccessible, but Johnston Canyon is actually accessible.”
Five active swift nests were confirmed in Johnston Canyon in 2021 – the highest number of active nests recorded in Johnston Canyon since 2004.
In 2020, three breeding pairs were spotted in the canyon, while only one or two active nests were recorded between 2005 and 2019.
Although the increase in the number of breeding pairs is a positive sign for the Common Swift population, it is still below the historical number of up to 12 active nests in the 1970s and early 1980s.
The Johnston Canyon Swift nesting colony was first discovered in 1919 and was the first confirmed inland nesting site in North America.
The bird can be recognized by its black plumage, its long, pointed wings and its unique notched tail.
“Although we know that the population has halved dramatically over the past few decades, there is no consensus on the cause of this decline,” Johnston said.
Although the causes of the decline are not fully understood, scientists suspect that it is partly related to changes in the food supply that may occur at one or more points in the swift’s life cycle.
Swifts, like many other birds, specialize in a diet of flying insects, and airborne pollutants kill insects.
“Air pollutants usually just reduce the amount of food for aerial insects,” Johnston said, noting that many other insect-dependent species aren’t doing well either.
“These are in general, in all areas, creatures that depend on insects, and the number of insects is decreasing because of the chemicals that we use,” she added.
“If they rely on that as food and the amount goes down, it probably affects the population.”
Swifts may also be sensitive to climate change, likely because waterfall nesting sites are likely to be affected by decreasing snow cover and melting ice.
However, Johnston said climate change can also lead to what’s called a time lag between the timing of things in a species’ life cycle.
“For these guys, it would be a lag between when these bugs are available and when they need them the most in their lifecycle,” she said.
“That’s about when they lay an egg and really need the energy, or when they’re feeding the chicks,” she added.
“If there’s a lag between when there’s a lot of food and when they need that food, again there’s going to be a population decline and we’ve seen that in many other species.”
Canadian Wildlife Service researchers conducted a study on the diet of black swifts about 40 years ago.
The Banff researchers figured they could track this now by collecting bird droppings, which is the only real way to know what specifically the swifts eat here.
“If we can find out what they’re eating now, it’ll be interesting to compare that to what they were eating before the population decline and we can see if there’s a difference,” Johnston said.
Researchers will examine bird poo under a microscope and look for exoskeletons.
“We can look at these exoskeletons in their feces and see what kind of insects they’re eating,” Johnston said.
“Ants against beetles? We can see how big, how many, and what general type of insects are they eating. »
The new technology means researchers can also use meta-DNA barcoding, which essentially means that DNA is extracted from poo.
“In this DNA soup, there are little segments of different species…” Johnston said, noting that he can be compared to hundreds of thousands of species in a DNA database.
“With just one scan, we can see all the different species they eat. It doesn’t tell us how many and it doesn’t tell us what size class, but it will tell us what species they eat.
Parks Canada has experimented with other innovative techniques to monitor Johnston Canyon Black Swifts.
Researchers have already managed to locate nesting birds with non-intrusive thermal cameras – which are also used to detect wildfires or ensure prescribed burns are over.
Johnston said swifts are difficult to detect because they nest in cold, dark places.
“We figured if these guys were hotter than their ambient environment, it should show up in these cameras and we found out it was,” she said.
“When you look at a cold cliff wall, you can see the outline of a bird or a baby bird sitting there, so that’s now the main way we can tell if a nesting area is active.”
Time-lapse cameras, which are also considered non-intrusive, are also used to keep an eye out for birds.
The researchers set the cameras to take pictures every hour.
“We can tell when the adults come and go, when do they come back in the spring, when do they lay an egg, when does the baby leave in the fall,” Johnston said.
“It also tells us how often the adults come and go to provide the young with food and how that can change over the season.”
The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) listed the Common Swift as endangered in 2015 and the species became federally protected under the Species at Risk Act in 2019. populations having fallen by more than 50% in the last 40 years.
Although little is known about the biology of the common swift, the species is thought to mate for life and live up to 16 years.
Black swifts also lay only one egg per season and have a long breeding period of seven weeks, with chicks not fledging until late September.
Nesting duties are shared by the parents, with the male and female trading shifts during the incubation period.
It wasn’t until 2012 that swifts were first discovered to fly to South America to overwinter.
Several Colorado birds were tagged with tracking devices, which indicated that their wintering grounds were in the Amazon rainforest of Brazil. There was also a reported sighting of a black swift in Tambopata, Peru in 2012.
However, COSEWIC says there is no information on whether the swifts that breed in Canada overwinter in the same area. Canada is home to approximately 80% of the North American population. “Indeed, the wintering range of birds from the various breeding grounds in North America remains to be determined,” according to the group’s report on the status of swifts.
Johnston said the birds, which are faithful to their nesting sites, are expected to return to Johnston Canyon in May.
“They’re in the Amazon and they’ll come back in the spring, and that’s a really critical time for them,” Johnston said, noting that nesting time is one of the most sensitive times for birds.
“They look for suitable nesting sites and they look for places where they won’t be disturbed and where they’ll be safe from predators.”
Johnston said Parks Canada is excited to see what happens this spring given that last year saw the highest number of active nests and successful fledglings since 2004.
“It’s long,” she said. “We hope that maybe the path they started on with this increasing trend will continue and maybe we will see more people coming back this spring.”
To ensure endangered swifts have space and safety to nest and raise their young, Parks Canada will implement the annual official closure of off-trail use at Johnston Canyon from May 1 to November, 1st. 15.
Officials say visitors can help with swift conservation efforts by staying on the dedicated trail and respecting the closure.
“It’s a rare bird and we literally have a handful of known nests around the province, in fact across the country,” Johnston said.
“Despite being somewhere we all like to go, it’s important to know that it’s quite a unique place and if we disturb the nests, it’s not like we have another place nearby where they can go.”
The recovery strategy for the Common Swift is still being finalized, under the leadership of Environment and Climate Change Canada.
The document will describe the threats facing the species as well as the measures to be taken to save the Common Swift.
“It will also define critical habitat for these types and Johnston Canyon would be one of those critical habitats,” Johnston said.
The only other known nesting site of the Common Swift in Banff National Park was discovered in 2020 in the backcountry of the Egypt Lake area.
Confirming nesting sites can be difficult, especially since adult birds often don’t visit nesting sites until late in the evening. It is believed that there were fewer breeding pairs there last year, with a peak number of five in 2020 and two in 2021, although this is not conclusive.
“These guys are so secretive and so fascinating,” Johnston said.