Field Methods


Population Surveys

Surveys allow us to track the status of remaining Loggerhead Shrike populations and to facilitate research on population demographics, habitat requirements and genetics. We are focussing our efforts on historic breeding sites and areas with a concentration of suitable habitat, where we have the greatest chance of finding shrikes.


Banding

We are conducting color-banding studies during the breeding and non-breeding seasons.  By marking individuals with unique color band combinations, we can gather valuable data on individuals that are re-sighted, without the need to re-trap birds. This includes data on year-round population demographics, on migration routes and on wintering areas.

Our banding focuses on adult shrikes, rather than nestlings, to decrease any risk that might be associated with removing young from the nest. To get the data that nestling banding would normally provide, we instead use other approaches, such as banding young as fledglings, once they are old enough to hunt for themselves, as well as analysing stable isotopes, genetic markers and trace elements.

 Photo credit: Lydia Dotto, ImageInnovation Photography

Photo credit: Lydia Dotto, ImageInnovation Photography

We have developed a banding protocol for Loggerhead Shrike to ensure safe and efficient:

  • trapping

  • handling

  • marking using leg bands

The banding scheme marks birds with a 4-colour leg-band combination, that provides a unique identifier for each bird, allowing it to be tracked from season to season. We provide training for banders on using specialized traps, applying the bands and other important considerations.

The North American Banding Council has adopted our protocol as standard operating procedure for banding this species.


Monitoring

Through the combination of monitoring and banding, we can learn crucial information about Loggerhead Shrikes, including:

  • whether they return to the same breeding site year after year

  • whether they migrate after the breeding season or remain on the same territory throughout the year

  • where they go after their young have fledged

  • the age of the birds within local populations

  • survival rates

  • how populations change over time the connections between breeding grounds and wintering grounds

  • how many birds pair, how many lay eggs and how many of those eggs hatch

  • how Loggerhead Shrikes use their habitat

During the wintering season, banding and monitoring will also help to identify if there are differences in the habitat used by males and females and by adults and juveniles. It will also help to identify the factors affecting shrike survival during this critical but poorly understood stage in their life cycle. Through monitoring, we can also track the number of eggs each pair lays in order to determine whether low reproductive success is contributing to shrike declines in certain areas.


You can help!

We are developing monitoring protocols that citizen scientists can use in in targeted priority areas. Our goal is to establish a network of “Shrike Force” volunteers across the species range. Become one of these dedicated citizen scientists who:

  • conducts surveys

  • works in collaboration with banders

  • conduct regular monitoring to determine site re-use, population turnover and other important measures of shrike population health