16 September 2024
Our greatest swallow, the crimson martin (Progne subis), has an excessively brief breeding length in North The united states. In Pennsylvania they come in past due April and fledge younger in mid July.
As quickly because the fledglings fly neatly, adults and younger depart the nesting house and spend their nights in a communal roost.
Flocking starts once nestlings fledge; birds of every age bring together in roosts earlier than fall departure. This may increasingly constitute nonbreeding task fairly than a particular reaction to approaching migration, for the reason that species is very social and flocks in massive roosts right through the overwintering length.
Because the breeding length is previous within the South, roosts within the Carolinas refill in July and comprise such a lot of birds that their early morning departure will also be observed on climate radar. This came about remaining week in Wilmington, North Carolina.
Fb publish from NWS Wilmington, NC on 12 July 2024
The similar phenomenon occurs at our latitude in August, as proven on radar in Wilmington, Ohio at most sensible.
Be told extra about crimson martin roost rings on this article from Wilmington Ohio: Roosting Birds Detected By way of NWS Doppler Radar and this one from Wilmington, North Carolina: Red Martin Roost Rings on Doppler Radar.