Two Canada lynx kittens from a family of five captured on a remote camera in Kluane, Yukon Territory last summer. When food is abundant, lynx have big families, like this one. When food is not abundant, females have fewer kittens or may forego having kittens altogether. Kittens stay in their mother’s den for several weeks after birth in May. In the peak of the summer, they begin to explore the world outside their den. This camera captured images of the family on one of its first trips out of the den.
Females will soon be establishing new dens and having new litters of kittens in Kluane. Food is abundant for lynx in the study area, and researchers expect big families again this year.
Photo and post by Darcy Doran-Myers.
The winter! the brightness that blinds you,
The white land locked tight as a drum,
The cold fear that follows and finds you,
The silence that bludgeons you dumb.
The snows that are older than history,
The woods where the weird shadows slant;
The stillness, the moonlight, the mystery,
I’ve bade ’em good-by—but I can’t.
– Robert Service, “The Spell of the Yukon”
I spent January of this year in the boreal forests of Kluane, Yukon. My goal was to collect pictures, fur samples, and tracks of Canada lynx in order to estimate density of lynx in the Kluane area. My Master’s project compares methods of density estimation to improve lynx research and management. Every few months I head to my field site in Kluane. I have experienced every season of the year in the Yukon, from the midnight sun in summer to the deep dark and cold of winter. No time of the year is quite like January.
Most of my time in Kluane, regardless of season, is spent hiking. This becomes particularly challenging in winter. This year, temperatures dipped to -35 Celsius and snow was thigh-deep in many places. Bailey (my field assistant/ hiking buddy) and I looked to lynx for advice on how to traverse long distances in deep snow. Lynx have disproportionately large feet, making them look funny in summer but helping them keep up with their prey in winter. Their feet function as snowshoes to distribute their weight and help them float on top of the snow. So, Bailey and I got some snowshoes. Not just any snowshoes; modern, lightweight snowshoes were ineffective in snow that deep. In order to make it to all our remote cameras and fur snag sites, we had to borrow extra-large, old-school snowshoes from a local outdoorsman. After a steep learning curve where we learned to walk without tripping (sometimes), the snowshoes became indispensable to our everyday hikes.
Cold temperatures were less easily dealt with. Lynx grow big fur coats every winter, with a beard around their neck for a scarf and thick fur between their toes for boots. All Bailey and I could do was outfit ourselves in the human-made substitutes. No matter how much we layered up, we still lost heat throughout the day and had to manage it as best we could. When temperatures were low, lunch breaks to eat our (frozen) sandwiches were limited at five or ten minutes, or until the cold caught up to us. Taking off our mittens even briefly to check cameras or to make a note was painful. Camera screens wouldn’t work, handheld GPSs would turn off mid-hike, and even pen ink would freeze. The Yukon cold did not make our fieldwork easy.
Despite the deep snow and the deep cold, Bailey and I headed outside each day to take advantage of every hour of daylight available. A key lesson that I learned this field season is that tough conditions are not as tough when you have a friend by your side to experience it all with you. Long sunrises and sunsets, Northern Lights to light up the night, and expansive white landscapes can help counter the extreme conditions with extreme beauty. And the real reward for the tough times was a lot of data. We collected about 250 pictures of lynx and 100 fur samples for analysis in that month. Every successful camera or fur snag and every lynx track in the snow is another piece of the puzzle to understanding lynx populations and improving our management of an ecologically, economically, and culturally important wildlife species.
I will return to Kluane for the last time in June. I look forward to experiencing yet another side of the North. By June, everything will have turned from bright white to bright green. The winter challenges of cold and snow will be exchanged for mosquitoes and mud. Long days will keep me outside for hours on end, and I look forward to returning to camp every day tired and happy. But I will certainly miss the Kluane winter and everything it offers. Again in the words of Robert Service:
There are hardships that nobody reckons;
There are valleys unpeopled and still;
There’s a land – oh it beckons and beckons,
And I want to go back- and I will.
– “The Spell of the Yukon”
Photo from Kluane trail cams courtesy of Darcy Doran-Myers
Most people can remember an instance where a bird collided with one of the windows of their home. Most people don’t know is that this has been identified as one of the largest human-related causes of bird deaths in Canada. Many studies have attempted to estimate the exact number of mortalities however, instead of coming up with an accurate number, multiple biases have been identified. The largest of which being the removal of a dead bird from below a window by a scavenger before it can be recorded.
-A house cat drags a bird carcass away from a window where it had collided
The number of birds being removed by scavengers has been accounted for in previous estimates, however these previous scavenger studies have all taken place at wind turbines. There have been few carcass removal studies done in an urban environment and none of these have been used to determine a correction factor that can be used in determining a more accurate window collision estimate.
To learn more about the role scavengers play in an urban environment we conducted a carcass removal study at houses within Edmonton throughout 2015. The premise was simple: a dead bird and a time-lapse camera were placed below a window in the front yard of each house. After 1 week we returned to see if the carcass had been removed.
In the end 67.5% of carcasses were removed within 1 week, with the average time to removal being 3.46 days. The most common scavengers were Black-billed Magpies (61.6% of removals) and domestic or feral cats (16.1% of removals). There were also removals by American Crows, Blue Jays and Red squirrels.
-Black-billed magpies and squirrels were some of the scavengers responsible for removing bird carcasses from collision sites
Carcasses were less likely to be removed in the winter and the relative probability of a carcass removal was 7.6 times higher during mid-summer compared to mid-winter. Newer houses experienced a lower probability of removal compared to houses built before 1970. As well, developed neighbourhoods saw a lower probability of removal than undeveloped ones. These factors are similar to those factors we had previously identified as having a large effect on the likelihood of a bird-window collision suggesting those homes experiencing a larger number of collisions are also experiencing a higher number of scavenging events.
From these results, we came up with a correction factor for carcass removal by scavengers. 31.8% of carcasses were removed in the first 24 hours, which results in a 1.47 carcass removal rate. This means the number of carcasses detected in the first 24 hours needs to be adjusted by 1.47 to account for removal by scavengers. This rate is lower than the one developed from wind turbine studies that was used in creating the current estimate of bird-window collision mortality in Canada.
Using this removal rate and the citizen science data previously collected by the Birds and Windows project we estimated 957,440 (± 59,280 SD) birds are killed from window collisions at houses in Alberta each year. This is the most detailed estimate of bird-window collision fatalities in Canada as it’s based on the most detailed window collision study at houses to date and a carcass removal study located in the same area. Unlike previous studies, we did not extrapolate our results across the country. Our estimate is for Alberta, the area from which the data was collected. If we are to improve the current bird-window collision mortality estimate for Canada, more localized studies like ours are needed. Completing studies in each of the provinces will help reduce several of the existing biases in the fatality estimate at houses.
-Post and photos by Justine Kummer
Link to full text: http://www.ace-eco.org/vol11/iss2/art12/
Kummer, J. A., C. J. Nordell, T. M. Berry, C. V. Collins, C. R. L. Tse, and E. M. Bayne. 2016. Use of bird carcass removals by urban scavengers to adjust bird-window collision estimates. Avian Conservation and Ecology 11(2):12.
A lynx family walks by a camera trap set by Darcy Doran-Myers near Kluane Lake, Yukon.
Marcella Kelly, an Associate Professor at the Virginia Tech Dept. of Fish & Wildlife Conservation, will be presenting a seminar at the University of Alberta this week. Her talk will be in the Biological Sciences Building room M149 at 2pm on Friday, September 11.
Abstract: Remote camera trapping and molecular scatology have enabled researchers to gain valuable information on previously intractable, elusive top predators. For jaguars in Belize, camera trapping techniques have enabled us to examine the co-existence of multiple predators simultaneously to determine whether jaguars function as an umbrella species or whether meso-predators are suppressed by high numbers of the top predator. Additionally, using scat samples collected with the aid of detector dogs, combined with molecular scatology, we find evidence of a generally well-mixed jaguar population in Belize, yet a faint hint of population sub-structure exists, pointing to the importance of maintaining targeted wildlife corridors. For tigers in Nepal, camera trapping in the forested, hilly habitat known as the Churia, previously considered unsuitable, has revealed a healthy (albeit lower density) tiger population and a potentially thriving leopard population. Unlike Belize however, landscape genetics from molecular scatology in Nepal has revealed a highly structured tiger population with low levels of gene flow among tiger sub-populations. Habitat restoration or targeted translocations may be necessary to maintain genetic connectivity across the landscape.