Updated January 2020
Thank you for your patience, dear readers and craniacs! Read on for a plain-language report containing preliminary results from our genetic analysis of BC’s Coastal and Interior Sandhill crane populations, using moulted feathers, mostly collected by volunteers, as a source of DNA. We are still working towards a scientific publication.
Thank you so much to all the project participants, many of whom shared their knowledge of breeding locations or hunted for feathers. Visit the Field Season Pictures tab for images from the fieldwork portion of this project. We are not collecting feathers at this time.
Feathers for Phylogenetics: Divergence in Western Sandhill Cranes – a preliminary report for the public
Phylo-what? The backstory on Sandhill crane populations in BC
Why we did this study
How we did it
What we found
Phylo-what? The backstory on Sandhill crane populations in BC
You may be wondering why scientists would want Sandhill crane feathers for a Greek pastry. In biology, phylogenetics is the study of the evolutionary history and genetic relationships among groups of organisms. British Columbia has three migratory subspecies of Sandhill cranes: the smaller Lesser Sandhill cranes that migrate through the Central Interior, and breed in Western Alaska as well as Northeastern B.C.; the larger Greater Sandhill cranes that breed in the Southern and Central Interior, and the mid-sized Canadian Sandhill cranes, that breed along the coast (see maps below). This last subspecies has been grouped in with Greater Sandhill cranes in prior genetic analyses, but some researchers maintain that they exist as a separate group with intermediate body size, breeding range, and migration timing. B.C.’s crane populations are different sizes, have different habitat needs, use different flyways, and are under different threats in their winter habitats south of the border. Pacific Flyway and Central Valley Population cranes that breed in B.C. are protected in their staging and wintering habitats in Washington and California. However, in B.C. all cranes are managed the same way and are not considered threatened.
Sandhill cranes were almost driven to extinction by over-hunting in the early 20th century, until they were protected in North America in 1918. Since then they have rebounded due to conservation efforts as well as their adaptable and omnivorous diet. Still, we don’t know how many cranes now make up B.C.’s breeding populations, or even how the Interior and Coastal populations are related.
The coastal population, which breeds west of the Coast mountains, is likely by far the smallest in numbers. This population summers mainly in bog or muskeg habitat on islands from the northern tip of Vancouver Island to Southeast Alaska, and birds tend to earn their living off of small marine invertebrates in the intertidal, which is quite unique for Sandhill cranes. They may have become separated from Interior cranes during the last ice age. They may also be differentiated because of their unusual habits, habitat, and predators.
Why we Did this Study
Previous genetic studies of migratory Sandhill cranes either did not include samples from the West coast and Central Interior, or used genetic methods that are difficult to replicate. We wanted to find out whether Coastal Sandhill cranes are genetically distinct from their East-of-the-Coast Mountains relatives, the Interior Sandhill cranes, in order to improve our scant knowledge of crane populations in the province, and to help ensure that they and their habitat are well managed. We also wanted to raise awareness about Sandhill cranes and their habitat needs, since so many people confuse them with Great Blue Herons!
How we did it
In order to get samples for genetic analysis without trapping cranes, we chose to gather moulted (shed) feathers from known breeding areas in Coastal and Interior B.C. However, we soon found that there weren’t many known breeding sites with publicly available coordinates. So, we reached out to the birding community and the greater public, asked people to share their knowledge of Sandhill crane breeding sites, and if possible, to collect feathers and send them to us. In 2017 and 2018, scores of volunteers from all over the province sent us information about crane breeding areas and many gathered moulted feathers and mailed them in. We also worked with volunteers to do our own field collection. You can see where feathers and breeding location data were collected on our interactive map with the ‘feather sites’ button turned on (screenshot below). Sites where feathers were collected will appear as red dots. The participation of so many citizen scientists made this project possible. In fact, we wager that a project like this – collecting samples over such a huge and difficult to access area – would be impossible to conduct without the assistance of so many volunteers.
Often several feathers were collected at the same site. For our analysis, we wanted to include as many individual cranes from as many sites as possible, so we chose the freshest and most-intact looking feather from each collection site for DNA isolation. We also had tissue from dead cranes that were found at a few sites (including one we borrowed from a coyote east of Williams Lake). In all, 133 samples from the Coast and Haida Gwaii (120 and 13 respectively), 77 from the Interior, and 29 from other areas were included. The “other areas” samples came mainly from government and research biologists and museums that had previously collected blood or tissue from studies in SE Alaska, Washington, Oregon, and Ontario (see Table X on all the samples). To provide the largest yield of DNA for genotyping, we chose large feathers, that were no smaller than 10cm long, usually 20-35 cm in size. DNA was extracted from the feather’s quill (calamus).
From there, geneticists at UBC’s Genetic Data Centre isolated DNA from the samples and amplified 8 microsatellite loci from the DNA to reveal differences in alleles at these loci. Microsatellites are one of the many types of genetic markers available to measure genetic variation. An allele is one of a pair of genes that appear at a particular location on a particular chromosome and control the same characteristic, and can be passed on from parents to offspring.
We then used a variety of statistical methods to look at the variations in alleles across the samples to see how samples from different regions compared. This work is still in progress; updates will be posted here.
What we found
In short, so far we have found that there is a significant difference in the microsatellite DNA derived from cranes from the Coast and Haida Gwaii versus that from Interior-breeding cranes. Notably, the Haida Gwaii cranes appear to be even more distinct from Interior cranes, although the smaller sample size available for Haida Gwaii cranes could likely be a factor in this result.
One of the measures that we used to look at patterns of interbreeding and isolation was heterozygosity, which is basically a measure of genetic fitness. The more a population interbreeds with other populations, the higher the heterozygosity will be, and conversely, the more inbred they are, the lower it will be, on a scale of 0 to 1. Among our samples, all had fairly high heterozygosity (above 0.5). In relative terms though, the Interior cranes had the highest heterozygosity, Coastal cranes had lower heterozygosity, and Haida Gwaii cranes had the lowest. Lower heterozygosity is consistent with a smaller population breeding predominantly within itself, meaning that the Haida Gwaii population may be isolated and differentiating as compared with the Interior-breeding population. However, the lower sample size from Haida Gwaii may have an influence on these results.
We are currently completing statistical analyses to better describe the differences between populations. We look forward to sharing these results with you!
Fieldwork for this study was conducted on the traditional territories of the Haida Nation, Gitga’at First Nation, Kitasoo/Xai’xais and Heiltsuk Nations on the Coast, and the Secwepemc Nation in the Interior. We gratefully acknowledge all of these Nations.
To all those who provided breeding locations and samples
including many volunteers from all over B.C.
the Royal Ontario Museum
Dr. Matt Hayes and Dr. Gary Ivey (co-authors)
To those who provided funding and in-kind support
Habitat Conservation Trust Fund-Public Conservation Assistance Fund
BC Ministry of Forests, Lands, and Natural Resource Operations
National Geographic Society
The main proponents of this study are Dr. Ruth Joy, Statistical Ecologist in the School of Environmental Science and Adjunct Professor in the Department of Statistics at Simon Fraser University, Krista Roessingh, who wrote her MSc. thesis about Sandhill cranes and their habitat on the Central and North Coast with support from the BC Ministry of Environment, and Dr. Carol Ritland and Allyson Miscampbell at UBC’s Genetic Data Centre.
Feel free to contact us by email at firstname.lastname@example.org with any questions or information you’d like to share. We can also arrange a phone call if you prefer.
1.How long are SACR usually on territory before they make a nest and lay eggs? This would be extremely variable, but is there an average?
Pairs observed on the central coast take up at least parts of their territory as early as 2nd week of April, with nest initiation believed to be in the first week of May.
2. When do cranes moult?
The literature is not very clear on this for our migratory cranes. I have read that they moult between when chicks hatch and when they fledge, which is when they spend most of their time walking around with the chicks anyway, June and July. But I have also read that they moult gradually from July to October. See page 6 here for more crane moulting food for thought.
3. In this scenario, what is the best type of feather that we have a chance at – juvenile moulting or adult moulting?
You are more likely to find adult moulting feathers. During my last feather collecting stint, I searched within 100m of nests (after the cranes have left the nest site – usually within 2 weeks of hatching, although they may return to the same area to roost at night) and often found them right at the nest site, or laying on the ground or caught up in vegetation in the vicinity.
4. How many days/weeks after hatching is the chick able to walk around independently and find food with parents?
The ones we watched with a remote camera began to venture within a day or two, and within a few days disappeared from within view of the nest site. They reappeared after about 10 days to spend the night. If there are 2 chicks they hatch asynchronously within about 12 hours of each other. Often the second won’t live long. There are two film clips here: http://greatbearlive.pacificwild.org/tags/sandhill_crane
Three subspecies of Sandhill Crane occur in British Columbia (B.C.):
Lesser (Antigone canadensis canadensis), Greater (A.c. tabida), and
Canadian (A.c. rowani), the latter being of uncertain taxonomic status
(Cooper 1996). Historically, subspecies were delineated by morphology
and breeding range. Although several genetics studies undertaken to
resolve the question of population substructure in Sandhill Cranes
have found that A.c. rowani is not distinct from A.c. tabida and/or
A.c. canadensis, none have included samples taken from
coastal-breeding birds of the Pacific Flyway Population, which may be
subject to ecological as well as geographic forces of differentiation.
With a diet that has marine-derived components and is abruptly
different to diets across the rest of this crane’s range, with a body
size and bill morphology different from cranes found nesting north and
south of the coastal range, and with a different suite of predators,
these cranes are unique. We propose to collect non-invasive samples
(moulted feathers) from cranes breeding in coastal habitats as well as
in interior plateau habitats of B.C. Mitochondrial and nuclear gene
samples will be sequenced and compared across these regions, and
compared with samples from other populations in North America. The
results of this work will help to elucidate the population genetic
structure of cranes nesting west of the Rocky Mountains, and will help
to prioritize conservation needs for this species.
 Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). 2015. The Atlas of the Breeding Birds of British Columbia, 2008-2012. Bird Studies Canada, Delta, B.C. < http://www.birdatlas.bc.ca/ e > [2017 Apr 15].