Efforts to assess the height at which to maintain airport grassed
environments has produced conflicting results. Transport Canada
(2006) concluded that long grass programs could be implemented
to reduce gull populations; however, rodent populations could
increase, leading to an increased raptor presence. However, short
grass seems to discourage Canada goose nesting and reduces
rodent populations and therefore raptor populations. Beason
(2004) indicates that birds show a species-specific response
towards vegetation height. Ultimately, Transport Canada recommends
that each airport conduct site-specific studies to determine
optimal grass heights, depending upon which hazard species are
present.