terrestrial mammals

Pas de contenu pour le moment

Snowy owls are large birds living North of America and Eurasia, with white / spotted white feathers. They are migrant birds, but in an unpredictable way – they can winter as south as the American Midwest, as well as in the Artic circle.

 

A snowy owl ("Beatrix") with tag, in the arms of A. Robillard (Credits U. Laval)
A snowy owl (“Beatrix”) with tag, in the arms of A. Robillard (Credits U. Laval)

The snowy owl (Bubo scandiacus) is one of the major Arctic top predators, and a highly nomadic species. Contrary to other owls, it lives by day as well as night (it should be noted that nights are short or non-existent in summer close to Arctic, anyway). It is a large bird, spending the summers on a diet mostly composed of lemmings or other rodents. On winter, though, they have a broader diet, and different habitat uses have been noticed. For a long time, we haven’t known whether those were individual behaviors, with different individuals showing fidelity to the same wintering site or if they could change their wintering habitat from year to year.

To explore this question, The University of Laval (Québec, Canada) tracked 21 females by satellite telemetry using Argos PTTs between 2007 and 2016, to describe the behavior of wintering snowy owls breeding in eastern Canada and to examine factors affecting their wintering behavior. Complementary data, such as snow depth, small mammal abundance were also analyzed with the owls’ paths.

 

Snowy owls tracked by Argos satellite telemetry from 2007 to 2016 in eastern North America. Also depicted on the graph are the three capture sites: Bylot Island (star), Deception Bay (square) and Mary River (diamond). (Credits U. Laval)
Snowy owls tracked by Argos satellite telemetry from 2007 to 2016 in eastern North America. Also depicted on the graph are the three capture sites: Bylot Island (star), Deception Bay (square) and Mary River (diamond). (Credits U. Laval)

These 21 tracked owls allowed to record 42 complete wintering periods, 25 of which were spent predominantly inland (16 in the Arctic, 9 in temperate areas) and 17 in the marine environment (15 in the Arctic, 2 in temperate areas). Most individuals that were tracked for two consecutive years used the same wintering environment among inland or marine and also stayed at around the same latitude (16 out of 21), but not always the exact same area. This change could be linked with variation in food availability. Annual variations in sea ice dynamics may change the spatial distribution of seabirds and could explain the moderate site fidelity shown by snowy owls in the marine environment. There are evidences that lemming densities on Bylot Island affected some aspects of habitat use by wintering owls (no data elsewhere).

Wintering home range contours of the 21individual snowy owls tracked for at least one complete winter between 2007 and 2016. One to three individuals only are plotted in the same graph (different color for each individual) to facilitate visual assessment. (Credits U. Laval)
Wintering home range contours of the 21individual snowy owls tracked for at least one complete winter between 2007 and 2016. One to three individuals only are plotted in the same graph (different color for each individual) to facilitate visual assessment. (Credits U. Laval)

The snowy owls’ consistency in wintering environment and latitude may provide them with advantages in terms of experience while their mobility and flexibility on the precise site may help them to cope with changing environmental conditions.

References

Audrey Robillard, Gilles Gauthier, Jean-François Therrien and Joël Bêty, 2018: Wintering space use and site fidelity in a nomadic species, the snowy owl, Journal of avian biology, e01707, doi: 10.1111/jav.01707

Photo U. Laval, a snowy owl on Bylot Island.

Links:

Ecological studies and environmental monitoring at Bylot island Sirmilik National Park

Argos Users stories

A snowy owl (

18.10.2018 Animal tracking applications Where snowy owls are wintering?

Snowy owls are large birds living North of America and Eurasia, with white / spotted white feathers. They are migrant birds, but in an unpredictable way – they can winter as south as the American Midwest, as well as in the Artic circle.   A snowy…

16.10.2018 EUCAW Speakers Argos-4 coming soon: a new momentum for the Argos system

Argos is a collaborative, international satellite system dedicated to environmental monitoring that has been flying for 40 years. Today, thanks to 6 operational satellites, it provides global coverage via its polar orbits, a unique robustness thanks to a communication protocol fitted for harsh conditions, — one of its main advantages…
hammerhead shark

16.10.2018 EUCAW Speakers Hammerhead Shark research: Knowledge from the populations in the Canary Islands

HAMMERHEAD SHARK RESEARCH is a project that studies hammerhead sharks Sphyrna spp in the Canary Islands with the aim to contribute scientific base knowledge of these species in an understudied distribution. Information of hammerheads in this distribution is limited to the presence of two species (S. lewini and S. zygaena),…

15.10.2018 EUCAW Speakers The annual cycle of German adult Ospreys (Pandion haliaetus) – studies in the breeding and wintering areas as well as during migration since 1995 by means of satellite telemetry

During 1995 – 2011 we marked 28 adult Ospreys in NE-Germany with satellite tags working up to eight years. All except three males wintered in West Africa. The migratory paths followed while in Europe seemed much straighter and more directional compared to the migratory paths followed in Africa. This pattern was…

15.10.2018 EUCAW Speakers Year-round Satellite Tracking of Amur Falcon (Falco amurensis) reveals the longest migration of any raptor species across the open sea

The title for undertaking the most arduous of all raptor migrations, belongs certainly to the Amur Falcon, which is a complete transcontinental, transequatorial, long-distance flocking migrant. The principal breeding (mainly NE China) and wintering (mainly S. Africa) ranges are separated by both 70° of latitude and longitude. Details of the…
Photo_tortue_CHAMBAULT

09.10.2018 EUCAW Speakers Combining Argos and genetics to reveal connecting paths between juvenile and adult habitats in the Atlantic green turtle

At the European User Conference on Argos Wildlife, Philippine Chambault of IFREMER presents this fascinating project of the French Research agency IPHC-CNRS. Although it is commonly assumed that female sea turtles always return to the beach they hatched, the pathways they use during the years preceding their first reproduction and…
Tracking turtle brendan godley

04.10.2018 EUCAW Speakers Tracking turtles to inform conservation

Brendan Godley, of University of Exeter has been tracking turtles using the ARGOS system for 20 years and has been involved in collaborative projects that have tagged over 500 hundred animals across the world. This has led to fundamental and applied insights for the populations in question but also provided…
Photo showing animal with attached Argos transmitter on 9 February 2018 (Krista Hupman, NIWA)

03.10.2018 Animal tracking applications Understanding the movement of pygmy blue whales in New Zealand waters

There is little known for cetacean species such as pygmy blue whales, but they are at the forefront of protection policies around the world. The distribution of those whales around New Zealand are studied using Argos PTTs and goniometer. There are two subspecies of blue whales recognized in the…

01.10.2018 Flash news European Users Conference on Argos Wildlife

The European User Conference on Argos Wildlife will be held in Toulouse, France, on November 21st & 22nd, 2018.   All Argos users, manufacturers or potential users are welcome to attend this two-day workshop. When: November 21st & 22nd, 2018 Where: Toulouse, France More info  …

01.10.2018 EUCAW Speakers The missing link: pelagic prey field prediction for Southern Ocean marine predators

Southern Ocean predators tend to lead cryptic lives, which in many cases are spent mostly at sea. This makes their foraging behaviour inherently difficult to study. Furthermore, numerous species are threatened through direct human conflict (such as fisheries related mortality), climate driven change, or both. At the European User Conference…