Reconstructing Habitat for the Vaux's Swift

Bull, E.  2003.  Use of Nest Boxes by Vaux's Swifts.  Journal of Field Ornithology.  74-4:394-400.

Logging has diminished the amount of old growth forests over the past 100 years.  For many years now, forestry companies have replanted trees in areas which have been logged, and clear cuts are only clear for a few years until saplings take root and replace them.  However, despite this reforestation effort, much habitat is still lost because may species require either large, old growth trees, or the additional habitats provided by an old growth forest.

One example of such species, is the Vaux’s Swift.  This species of bird has a summer breading range from northern California, through Oregon, Washington and into the interior of British Columbia, from the coast into southern Alberta, northern Idaho and western Montana.  Vaux’s swift nest in deep, hollow cavities which form in old growth trees which have become infected by heart-rot fungi (Bull 2003).  Heart-rot fungi invade the heartwood (inner wood of the tree), and decays it to a point of collapse, forming a hollow cavity.

Because of logging practices, many trees do not live long enough anymore in order to develop heartwood, and subsequently become infected by heart-rot.  Most forests are secondary or even tertiary forests, which are not old enough to have developed hollow cavities.  In addition, dead hollow trees are cleared away during logging, so these have diminished also.

In an effort to re-establish nesting sites for Vaux’s swifts, Evelyn Bull began constructing artificial hollows out of pine (Bull 2003).  She used 2.4 cm by 30 cm (1x12 for all of you carpenters or Americans out there) planks of pine to create a square shaft 28 cm wide and 3.5 m long.  These were hung on trees at a height between 10 and 15 meters, in three different forest types: late-seral stands of Grand Fir (the swifts natural habitat), harvested stands of Grand Fir, and mature stands of Ponderosa Pine and Douglas Fir.  99 boxes were constructed and distributed approximately evenly throughout the three forest types.

Over the four year period, 30 nest boxes were used by Vaux’s Swifts, with a total of 51 nest attempts and a 53% success rating.  Percentage of boxes used over time changed, with the first year having all ten boxes used in the late-seral Grand Fir stand.  Over the four year study the percentage shifted to most boxes being used in the pine and harvested stands, rather than the late-seral Grand Fir stands.  Bull suggests this is because the swifts will nest in other habitats, but needed to discover nest sites available in habitats other than the late-seral Grand Fir stands.

This study has provided a number of key highlights in Vaux’s Swift restoration efforts.  First, it is possible for swifts to exist in habitats other than old growth forests.  It seems they only require old growth forests for the nesting habitat, and if alternate nesting sites are available, the swifts can nest in 2˚ or 3˚ forests.  Second, the study provides examples of nesting sites, their construction and placement, all steps which are easily replicatable.

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Mountain Caribou and Snowmobilers: A New Harmony?

Simpson, K., and E. Terry. 2000. Impacts of Backcountry Recreation Activities on Mountain Caribou – Management Concerns, Interim Management Guidelines and Research Needs. B.C. Minist. Environ., Lands and Parks, Wildl. Branch, Victoria, BC. Wildl. Working Rep. No. WR-99. 11pp.

Price, G., Roorda, L.  2006. Four Year Summary of the Quesnel Highland Snowmobile- Mountain Caribou Monitoring Project, Cariboo Region.  Ministry of Environment, Environmental Stewardship Division.  Caribou Region.

            (accessed via Google on March 1, 2011)

In 2000, the mountain caribou (Rangifer tarandus-caribou) was nationally listed as “threatened”, and provincially red listed.  A suspected conservation concern for these mountain caribou is backcountry winter motorsport activities, such as snowmobiling, heli-skiing and cat-skiing (Simpson & Terry 2000; Price & Roorda 2006).  Winter territories for the mountain caribou consist of alpine glades, where snowpack is high and powder is common.  This makes it difficult for predators, such as wolves, to reach them.  Not only must they travel through snow typically deeper than 2 m, but also uphill. 

This type of wintering territory is common throughout the interior of British Columbia.  There are 13 subpopulations of mountain caribou living throughout the interior.  Two populations inhabit Wells Gray Provincial Park; one in the north end and one in the south (Simpson & Terry 2000).  The southern population ranges between Clearwater and Wells Gray park, in the North Thompson Region.  Snowmobile concerns here are less prominent inside the park than out.  Just south of the park, and still within the mountain caribou’s territory, lies the town of Clearwater.  Snowmobiling is popular in the Clearwater Forest District, and caribou-snowmobile conflicts are common. 

The northern subpopulation of mountain caribou in Wells Gray park are also subjected to snowmobile encounters.  Here they primarily occupy the Quesnel Highlands, which offers prime territory for snowmobiling.  Access to this area is frequent from various towns, including 100 Mile, Likely, Horsefly and others.  Common mountains used for snowmobiling include Mica, Boss and Deception Mountain, as well as Cameron Ridge.  All of these mountains lie within the northern Wells Gray subpopulations winter territory.

Ideal snowmobiling conditions, unfortunately, match these ideal winter habitats for the mountain caribou.  Alpine ridges offer scenic views and a challenge to reach for snowmobilers, but these same types habitats also are the preferred late-wintering habitats for mountain caribou (Simpson & Terry 2000).  Noise pollution from motorized vehicles, such as helicopters, snow-cats and snowmobiles, have a tendency to deter caribou.  Also, mountain caribou have a keen sense of smell, and they typically avoid areas where they can smell humans.

A primary reason for caribou to winter in alpine territories is the deep powder which accumulates at high elevations.  Caribou have long legs and large hooves, excellent for travelling through deep snow.  Predators such as wolves have much shorter legs, and have more difficulty travelling through deep snow.  This makes for an easy escape in the event that wolves attempt to hunt caribou while in the alpine.

If the mountain caribou are inhabiting areas where snowmobile or snow-cat’s have accessed recently, their predators suddenly have an advantage.  The weight of the sleds compacts the snow, creating a track in which wolves have a much easier time travelling along.  Following a snowmobiles tracks into the alpine can lead wolves into the caribous wintering territory with ease.  While snow-cats are heavier than snowmobiles, and create larger tracks, they are much less common than snowmobiles thus pose less of a concern.

But it would seem snowmobilers are willing to sacrifice some prime sledding territory in order to help out this struggling group of reindeer.  In 2002, Price and Roorda began a four year study in collaboration with various local snowmobile clubs in the Quesnel Highland.  It was a monitoring plan to collect baseline data about snowmobile use in the area, with “voluntary closure zones” (VCZ) and “caution zones” (CZ).  VCZs were areas deemed critical caribou habitat, and CZs were defined as sensitive caribou habitat.  Although the study itself did not include areas within Wells Gray park, it included the Wells Gray North mountain caribou subpopulation.

These VCZ and CZ regions were mapped out by the Ministry of Agriculture and Lands (MAL) over four zones (A through D).  The plan involved the cooperation of local snowmobile clubs from 100 Mile House, Quesnel and Williams Lake, who spread word of the closure and caution zones as well as agreed to adhere to the voluntary rules.  The Ministry of Environment (MOE) also collaborated with this plan.

To determine snowmobile activity in caribou territory, flights over the study area were taken every weekend.  The flights looked for both caribou as well as snowmobiles/snowmobile tracks in the VCZs and CZs.  Global positioning systems were used to record the locations of snowmobilers as well as caribou. 

The results of this study were uplifting.  In the four year study, 708 snowmobiles were observed.  241 caribou were observed directly, and an additional 362 were estimated to be in the area, either by tracks or beds seen in the snow.  Of the 708 snowmobiles sighted, 627 were seen in the CZs, and only 51 were seen in the VCZs.  This was a 92.5% compliance of snowmobilers.  There were only a total of 21 encounters with snowmobilers and mountain caribou over the four year study.

In my own opinion, this study is uplifting on many ways, but also leaves me wondering.  I’m ecstatic to hear that local snowmobilers willing to sacrifice some sled terrain in order to assist a struggling species.  I’m glad that this study is a collaboration between both the government and local people.  I believe the best way to encourage conservation is to engage the public and this study did just that.

Some concerns of mine are the lack of previous data.  Did snowmobilers use the VCZs before?  Were they already not frequently accessed, or was there a significant decline in usage once this voluntary plan was initiated?  I’m also curious as to who these snowmobilers were, and if they had any idea they were in a voluntary closure zone?  Explanatory signs were erected, but would everyone have stopped to read them?

In conclusion, I strongly supports plans such as this one.  Engaging the public is a step in the right direction for conservation.

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