Large Owls & Diurnal Birds of Prey
This group of species are well suited as biological indicators, but perhaps their most important quality is that they are able to provide early warning signs of major changes in the landscape or environment. Many populations of raptors have seen a worldwide decline, and many of them need human intervention to increase reproductive success or survival, especially in fast changing environments. Every year, an increasing number of owls and diurnal birds of prey are admitted to rehabilitation facilities with injuries related to human activities. Although the majority of these casualties are non-releasable into the wild, some orphaned individuals can be successfully fostered into active wild nests.
Objectives
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Identify the size and composition of the raptor guild using the study area
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Estimate the breeding population size within the study area
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Document nest location, protect existing nests and/or provide new nesting platforms
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Monitor breeding performance
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Use active nests to foster orphaned birds of prey and owls
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Build and maintain a long-term database on habitat preference and nesting success
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Trap and mark raptors during post-natal dispersal and migration and collaborate with organizations and institutions to improve understanding of these species’ biology and ecology
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Inform land managers, other stakeholders, and the public about the project
Ground-based Raptor Surveys
The main methods used to assess the size and composition of the raptor guild within our study site are nocturnal owl surveys and roadside raptor surveys. We have listening spots identified for owl surveys and additional points suitable for detection of diurnal birds of prey. These points are at least one kilometer apart, and surveys are carried out at least once every month of the year. At each point we spend 15 minutes scanning the sky and the surrounding environment. We also record any incidental observations that are outside the survey interval or birds seen during travel between points. Incidentals are also recorded on any outing, regardless of what activity we are doing.
Nest Searches
Large stick nests are best located late in the Fall once the leaves are fallen, or in the Spring before leafing out. There are two main methods we use to search for these nests: The first method is done by driving slowly along existing roads and scanning forest patches as we pass by. Each observed nest is then assessed on foot, and we record its precise location to allow re-visits during the breeding season. The other method is visiting larger forest patches within the study area and searching on foot for existing stick nests. During these transect surveys, two members walk parallel transects 10 - 20 meters apart, depending on the terrain and forest type. Each nest is mapped, and we return during the active breeding period to assess if it's being used.​​
Assessing Vital Rates & Fostering Orphaned Birds
At each discovered nest, we assess nest stability and accessibility. We return to each nest during the breeding season at least once to assess occupancy. We try to document nesting success either by climbing the nest or observing from the ground. Active nests that are considered weak or sustain damage during the nesting season are reinforced or replaced with an artificial platform which mimics the natural nest.
We also collaborate with rehabilitation centres that rescue or receive orphaned birds of prey and use our known active nests as foster homes. We also provide support to institutions or agencies tasked with bird care and raptor management, to offer the best chance of survival to young birds needed to be relocated due to public safety concerns.
Marking Adults & Young
Whenever possible, we band the young in the nests. We also trap adults during Spring and fall migration, and juveniles after fledging. Banding birds allows us to investigate post-natal dispersal, mortality, migration, and recruitment.