Winter surveys - COMMUNAL ROOSTS

Because roost sites concentrate birds in one spot, they present good opportunities to count birds. If you know of a site that is regularly used by multiple roosting birds, then consider conducting regular surveys of the birds as they come in to roost. Also, keep an eye out for birds travelling consistently in one direction at dusk or dawn, as you may be able to follow them and find a roost. Species most likely to form roosts include geese, ducks, shorebirds, gulls, vultures, crows, robins, starlings, and blackbirds. Most roosts occur at night, requiring counts to occur as dusk approaches. Coastal waterbirds (e.g., shorebirds) often roost during high tide, rather than at night. Although small songbirds are not usually thought of as forming communal roosts, species such as house sparrows, finches, and even kinglets and creepers, will sometimes congregate in one spot. Reports of these species would be welcomed too.


  • Pick a location where you know birds gather to roost (roost sites do not have to be in your block).
  • Record the latitude and longitude of the roost site (note that this may not be exactly where you observe the birds from) and give the site a name. Instructions on how to provide location information are here.
  • On each visit, try to arrive before birds start to enter the roost and stay until it is completely dark, so that you do not miss birds. For high tide roosts, arrive before the tide peaks and stay until high tide.
  • Visit as frequently as you are able (ideally at least once every two weeks, but even 1-2 visits are valuable) and count birds as they come in to roost.
  • Also record any other unusual species seen in the area, especially birds of prey, which are often attracted to roosts to hunt.
  • Data can be submitted as a stationary eBird checklist using the roost site as the location point; please write “CT Bird Atlas roost survey” in the comments box and share with the ctbirdatlas account (for instructions on how to do this, go here). Alternatively, data can be submitted on the paper form here, again providing the latitude and longitude for the center of the roost site.