Owl Calls 101

This is the time of year to get outdoors and listen for owls calling. From mid-March to early May is owl breeding season in northern Alberta, so they’re actively calling to defend their territories. In previous years, I would be out right now doing owl surveys for my PhD research, but this year I’m stuck in my office trying to finish writing my thesis. You may not have seen very many owls, but they are out there, and you’re far more likely to hear them than you are to see them. Owl species have easily recognized calls, and learning them is pretty easy because they are so distinctive. So for all of you that are interested in learning owl calls or heard one recently and want to find out what species it is, here is an easy guide to owl calls! Below are details for species found in northern Alberta with clips from recordings I’ve collected during my PhD research over the past few spring seasons.

For best listening of these clips use headphones and increase the volume if need be, some clips are more faint than others‎.

Great horned owl

You all know this one! This is probably the most typical sounding owl call. It consists of 4-5 hoots in a distinct pattern. Both the female and male will call in duets, and they’re relatively easy to tell apart, the female call is a bit higher in frequency (i.e. pitch) than the male. Great horned owls are very common, so you’ve got a good chance of hearing one. They are Alberta’s official bird, a great choice considering they are found everywhere in Alberta and in almost every kind of habitat. In the first clip you can here a female Great horned owl calling very close, and in the second clip you can hear a male and female duet:

Great horned owl female:

Great horned owl male and female calling in a duet:

Barred owl

Barred owls will also call in duets, though it’s harder to distinguish the male and female calls of this species. Their typical territorial call is the two-phrased hoot, commonly referred to by its mnemonic: “Who cooks for you, who cooks for you all?”

Have a listen to this clip and see if you recognize this call:

Barred owl two-phrased hoot:

Another call that can be often by heard is the ascending hoot, this call has a similar ending as the two-phrased hoot. Here is a clip of what that sounds like:

Barred owl ascending hoot:

 

Great gray owl

This species of owl has the lowest frequency call of all the owls found in northern Alberta. It consists of several low hoots in fairly rapid succession. Take a listen to this clip of a great gray owl male calling:

Great gray owl male calling (with a boreal owl calling in the background):

The female great gray owl will also give a ‘whoop’ call, this isn’t very commonly heard, but it sounds pretty neat. Here’s a clip of the ‘whoop’ call:

Great gray owl female ‘whoop’ call:

 

Boreal owl

This species tends to call quite consistently. They are generally found in coniferous forest and are relatively common in the boreal forest of northern Alberta. Its call sounds like a trill:

Boreal owl call:

 

Northern saw-whet owl

The sound of this species call sounds like the backup beep of a truck reversing:

Northern saw-whet owl call:

 

Northern pygmy owl

This species is more commonly found in the western part of the province in the foothills and mountains, however I have heard them in northeastern Alberta as well. This is Alberta’s smallest owl species. They are active and hunt during the day and can be heard calling during the day as well. This species call is quite similar to the Northern saw-whet owl but with greater spacing between the hoots:

Northern pygmy owl call:

 

Long-eared owl

This species’ call is probably the most boring owl call, but it’s exciting to hear them because they are not too common. It gives a series of simple hoots that are fairly widely spaced out:

Long-eared owl call:

 

Julia Shonfield is a PhD student in Erin Bayne’s lab researching the impacts of industrial disturbance on owl habitat use and distribution in relation to oil and gas infrastructure in northeastern Alberta. For her research she conducts owl acoustic surveys and has focused on three of the species mentioned above: great horned owls, barred owls, and boreal owls.

Field Fun Friday

What do -38°C, a spacesuit and a wooden post have to do with songbird research?
I could only hold the camera for a couple seconds before my fingers froze. My field partner, Logan, and I had just snowmobiled a half an hour from our truck parked on an ice road ~80 km south of the Nunavut border, in the tundra of the NWT. We were not actually wearing spacesuits, but our big onesies, snowmobile helmets and steel-toed winter boots made it look like we were. Our task was to collect acoustic recording units (ARUs) deployed by Environment & Climate Change Canada (ECCC). The ARUs were deployed last year when the ice road was open, but started recording in the spring, after birds had arrived. Winter is the only time this northern boreal/tundra transition area is accessible. 100 ARUs, mounted on trees and wooden posts (when there are no trees), span a 400 km south-north transect along the ice road. After retrieval, recordings will be analyzed to identify bird species. This marks the start of a long-term monitoring project to identify and track the northern limits of songbird ranges, a topic of great importance in the face of a changing climate. Students from Dr. Erin Bayne’s lab collaborate with ECCC on songbird research using ARUs.
Collaborators: Samuel Haché (Environment and Climate Change Canada)
Location: Tibbitt to Contwoyto winter road, Northwest Territories

-Post and Photo by Emily Upham-Mills

The role of urban scavengers in estimating the number of birds killed by window collisions

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.

Volunteering in the Owlery for the annual School of Witchcraft and Wizardry event

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Lively looking owl specimens demonstrate to kids a wide variety of species

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Special adaptations of their wings, skull, and talons, make owls formidable predators

Several grad students in our lab helped run the owlery again this year at School of Witchcraft and Wizardry, an annual science outreach event run by Let’s Talk Science at the University of Alberta. We taught kids a variety of facts about owls including how they are adapted to their environment, how they hunt, and how they communicate.

The students got to listen to several different species calls recorded from the wild. We had a variety of owl specimens and new this year we brought in mammal specimens (a hare, mouse, vole, and a squirrel), to show the kids what kinds of prey owls will eat. The kids really seemed to enjoy it and so did we! It was great seeing their eyes light up as they learned about owls and listened to different owl calls, there was even one kid that did a great impression of the calls of four different owl species!

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Participants listened to audio recordings of owl calls

Photos and text by Julia Shonfield

Fall Ferruginous Hawk Migration

Hawk migration is on!
University of Alberta M.Sc. student and Hawkwatch International Research Biologist Jesse Watson has been tracking Ferruginous Hawks on their breeding grounds and migratory routes. Read the full story in his Hawkwatch International blog

An adult Ferruginous Hawk equipped with a satellite transmitter backpack

An adult Ferruginous Hawk equipped with a satellite transmitter backpack

Current migration tracks for 18 adult male Ferruginous Hawks from southern Canada.

Current migration tracks for 18 adult male Ferruginous Hawks from southern Canada.

-Post and Photos by Jesse Watson

Where do the Warblers Wander? Migratory Connectivity of Canada Warblers and Connecticut Warblers

This summer, biologists from the University of Alberta and the Smithsonian Migratory Bird Center were back in action in Alberta’s boreal forest. In an effort to find out more about where boreal breeding birds spend the winter, and what routes they take during migration, our crews have been putting tracking devices on a variety of bird species including: Broad-winged hawks, Rusty Blackbirds, Olive-sided Flycatchers, Common Nighthawks, Palm Warblers, Canada Warblers, and Connecticut Warblers as part of the Migratory Connectivity Project.

I have spent the last two years researching Canada Warblers for my M.Sc. thesis, so I jumped at the opportunity to work with the Smithsonian’s Michael Hallworth (post-doctoral fellow) to catch both Canada Warblers and Connecticut Warblers and fit them with light-level geolocators: tracking devices that record ambient light levels which are then used to determine locations. An estimated 85% and 95% of the breeding populations of these species, respectively, occur in Canada, and these neotropical migrants make the long journey to and from South America each year. Canada Warblers are listed as threatened in Canada, so there has been plenty of recent interest in finding out more about the drivers of population declines, and in what part of their range these impacts are occurring. Connecticut Warblers are highly under-studied, and known for secretive behavior during migration, so information on their migration ecology is scarce.  img_3031
Photos: Male Canada Warbler with distinct black necklace (left) and male Connecticut Warbler with full grey hood (right)

We headed out to Lac La Biche, Alberta to begin a whirlwind 10 days of “warblering”. Because both Michael and I had previous experience conducting research on Canada Warblers, and because I had worked on Canada Warblers in this area the previous year, we thought this species would be a good place to start. Using mist-nets, playbacks of male territorial songs and a decoy (“Agro Al” made by Hedwig Lankau) to lure them in, we set out to capture some birds. Within three days we had captured our quota of 15 Canada Warblers, including recapturing two of the males that I had colour-banded in 2015 (pictures here). This means these 10 gram birds had successfully migrated to South America and back, returning to the exact same breeding location in Alberta! We fitted all captured males with geolocators as well as unique identifying coloured leg bands to make them easier to relocate next year if and when they return to their breeding grounds.20160608_111640cawacrop220160608_104720Photos: “Agro Al”, our decoy, checks out a caterpillar while trying to lure in a territorial Canada Warbler (left); Anjolene fits a geolocator on a Canada Warbler using a leg loop harness (centre); This male shows off his geolocator light sensor, which will use ambient light to track his location during migration (right).

With the Canada Warblers taken care of, we set out to catch our second species, the potentially more elusive Connecticut Warbler. With our relatively limited knowledge of this species, we were anticipating a lot more difficulty finding and capturing them. We started our day planning on bushwhacking our way ~1 km to an area where this species had been previously detected. However, seconds after opening the door of our truck, we heard a Connecticut Warbler singing its heart out only 50 metres off of the highway. We hurried over and were able to capture the male fairly quickly and fit him with a geolocator. While we were processing our first bird, we heard another not too far away, and so the trend continued for the next few days, in which we caught our 15 Connecticut Warblers (including two in the same net!).

20160607_113110img_3027cawacrop3Photos: Michael extracts our first Connecticut Warbler from a mist-net (left); This Connecticut Warbler displays his new colour bands, which will be used to identify him next year (center); Michael fits a male Connecticut Warbler with a geolocator using a leg loop harness (right).

With the captures complete for this year, we now wait with anticipation until summer 2017 to recapture our males, collect the geolocators and find out where they’ve been!

-Post by Anjolene Hunt