Bicknell's Thrush was given species status in 1995, separate from Gray-cheeked Thrush.
Please note that routes are not consistently run, sites were not selected on a purely random basis, and a low percentage of sites are located outside of the Bicknells Thrush habitat distribution model.
Site selection was based on a GIS model of potential Bicknell's Thrush habitat that incorporates elevation, latitude, and forest type. Routes, consisting of five points spaced 200-250 m apart, were located within this habitat model if possible. A few sites are below the threshold and some cross it. An attempt to randomly select sites was made; however, the choice of sites was constrained by the availability of volunteers and the location of existing trails.
Survey methodology:
Surveys are conducted under acceptable weather conditions (no precipitation, temperature >2 °C, wind speed <32 km/h) from 1 to 21 June. Surveys are conducted between 04:30 and 08:00 EDT; most completed by 06:30 EDT. Observers listen quietly for ten minutes at each of the five stations Observers record the number of each focal species seen or heard during three time periods: 0-3 minutes, 3-5 minutes, and 5-10 minutes. If Bicknell's Thrush is not detected during or between point counts, surveyors return to each point and broadcast a one-minute recording of the bird's vocalizations, followed by a two-minute listening period. Playbacks are discontinued upon detection of one or more individuals. If no Bicknell's Thrush respond to the broadcasts, observers are asked to conduct follow-up playback surveys at dusk or dawn before 15 July.
Frequency of occurrence and relative abundance are calculated for each of the focal species. For Bicknell's Thrush, we also calculated the proportion of survey routes on which the species was detected by any means (10-minute point count, chance, playback, or follow-up). For between-year comparisons, we calculated the average number of individuals per point on a route by route basis. For each focal species, we averaged per-point values across routes to produce an overall index of relative abundance. This is calculated for all routes and for only those routes that have been surveyed continuously.
Mountain Birdwatch all species data variables include: FirstName, LastName, RouteName, Date, SurveyStartTime, CountLength, Temperature, CloudCode, WindCode, Occupancy, RoutePointNumber, SpeciesCode, TimePeriod, ObservationType, DistanceEstimate, and SurveyNotes.
Mountain Birdwatch playback data variables include: FirstName, LastName, RouteName, Date, RoutePointNumber, PlabyackStartTime, BITHresponse, NumberBITH, and SurveyNotes.
Mountain Birdwatch followup data variables include: FirstName, LastName, RouteName, Date, SurveyStartTime, FollowupEndTime, Temperature, CloudCode, WindCode, TotalPlaybacks, and NumberBITH.
Please also refer to our Disclaimer and Data Release Policy: <http://www.vtecostudies.org/MBW/datarelease.html>