At the Project:
Most nests are empty now.  A few scruffy adults still hang around sunning and
preening, and you may notice early stages of molt, the replacement of their
feathers, as they fly overhead.  Look for notches in the trailing edges of
adults' wings and tails where their first flight feathers have been lost.   









Since some of your former nestlings, now independent juveniles, may linger
around the project for a week or two longer if the foraging is good, this is
the best time to check them out.

Concepts:
How do you tell juvenile Tree Swallows from adults?
  • Juveniles have sooty gray upper bodies, wings, and tails (see below),
    without any traces of blue or green.
  • A few may show a very faint breast band.
  • They weigh about the same as adults but their shorter, rounder-tipped
    wings and tails make them appear smaller and chunkier.
  • Juvenile flight is a bit slower, weaker, and more "fluttery" than adults'.








When will juveniles get their adult plumage?
  • Juvenile molt to adult plumage begins a few weeks after fledging.
  • Molt is a gradual process, extending over several months.
  • Surviving juveniles complete feather replacement by late autumn.
  • Juvenile males will acquire the blue-green iridescent upper body
    possessed by all after-hatch-year (AHY) males.
  • Juvenile females will acquire the brownish-green upper body plumage
    that distinguishes second-year (SY) females from older ASY females.

While juveniles hang around, what are they doing?
  • Juveniles join adults foraging over fields and wetlands.
  • Some may beg at passing adults.
  • They often perch in groups on wires and trees, resting and preening.











  • They may land and sun themselves on roads, beaches, and other warm
    surfaces.
  • Juveniles sometimes approach nest boxes, fluttering around, perching
    on, and even entering them, especially if they still contain living
    nestlings.

Why do juveniles congregate at boxes that still contain nestlings?
  • We aren't sure.
  • They definitely aren't "helping out".  Their presence may actually
    interfere with parents trying to feed nestlings.
  • Perhaps they're "scouting" nest sites for next year.
  • Some may be trying to mooch a free meal from resident adults.

Question for the next Topic:  After Nesting.
  • What happens after nesting is complete?
  • Where will all your the swallows go and what do they do?

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Juveniles
Learn About Birds at Tree Swallow Nest Box Projects