Vancouver Naturalist_March 2012.pdf - Nature Vancouver

Conservation Matters
Conservation Section Members
Visit YVR to Discuss Wildlife Control
by J.M.Ryder
In 2011, members of the Nature Vancouver Conservation Section
were concerned to learn that unusually large numbers of ducks
had been killed by intervention at Vancouver International Airport
(YVR) during 2010. We are aware that the Wildlife Management
team at YVR is charged with the difficult task of managing local
wildlife in order to maintain the safety of aircraft and the travelling
public. However, we did not understand why the number of ducks
“culled” had risen from an average of 184 during 2005–2009 to
1486 in 2010 (and then fell to 261 in 2011).
After some brief discussions via e-mail, YVR staff offered to
meet with Nature Vancouver members, an offer that we gratefully
accepted. So on January 11, 2012, six members of the Conservation
Section met with Simon Robinson of YVR’s Environment
Department, Wildlife Management Consultant Gary Searing,
Wildlife Control Supervisor Dave Ball, and Operations Manager
Arnie Jassman. We spent a couple of hours around a table and then
enjoyed a tour of the airfield to gain a clearer perspective on the
nature of wildlife control activities.
At the meeting, Simon outlined the basics of wildlife management
at the airport and the circumstances that led to the unusually large
cull of ducks, as follows:
Three components to wildlife management:
(1) Habitat Management – priority is to minimize features that
attract birds (especially waterfowl and raptors), such as standing
water on the airfield, and nearby fish-processing plants.
(2) Active wildlife control – primarily harassment of birds
so that they move away (and stay away) from the airport. Wildlife
technicians have a variety of devices (described below) that they
use to observe and scare the birds; one to three controllers are out
on the airfield at all times. Sometimes it is necessary to kill birds,
especially ducks, when they directly threaten aircraft safety.
(3) Wildlife technicians monitor the wildlife (coyotes as well
as birds) and report on the effectiveness of their actions. All strikes,
culls (birds killed by intervention) and the estimated numbers of
birds moved by harassment are recorded. A “strike” is recorded
when there is physical evidence of a bird/aircraft collision (e.g.,
bird remains, damage to the plane), and when a “strike” is reported
by a pilot even if there is no physical evidence. (It may have been
a near miss, but that is still a very dangerous event.)
Increased Risk Late in 2009, it became apparent to the wildlife
team that the number of birds on the airfield was increasing (and
that this was not just a seasonal change). At the same time, control
practices had changed, resulting in less active control of birds
and more passive control, leaving more birds on the airfield. This
resulted in more raptors and ducks, and with increased strikes and
decreased culls the risk of a serious accident had become relatively
very high. (In December alone, five duck-strikes were reported,
with one of these involving six birds, while over the previous 10
years, there were 3 to 10 duck strikes per year.)
4 Vancouver Naturalist March 2012
At the same time, it was discovered that unexpectedly large numbers
of ducks were congregating on the airfield to roost at night, and
rather than staying in a particular area, these birds were moving
around unpredictably.
Introduction of “Hunting Strategy” Recognition of increased
risk required immediate action to address and reduce potential
strikes. So a conscious decision was made by the wildlife control
team to increase duck culls. This “hunting strategy” was based on
the premise that waterfowl will avoid areas where hunting occurs.
It was initiated in January 2010 and maintained throughout the
year. The strategy was successful in that it reduced the number of
ducks on the airfield, and since then, the lower numbers of birds
have persisted even though the number of ducks killed in order to
maintain an aversion to “hunters” has been significantly reduced.
Ducks killed by intervention* (culls)
2005 2006 2007 2008 2009 2010 2011
311 319 218 39 34 1486 261
* Culled birds were mostly Mallard, American Wigeon and
Green-winged Teal.
Raptor Trapping Program Raptors pose less danger than
waterfowl: because they fly singly, the likelihood of multiple strikes
is low. But they are still a significant hazard due to their large
body size. Raptors (including owls) are much harder to control by
harassment than ducks. They will move a short distance in response
to a firecracker, but then return. To reduce the risk of raptor strikes,
a raptor trapping program was initiated October 2010. The airport