Tweeters and OBOLonians,

I'm not usually a "nit-picker"; however, recent references to
"rookeries" of Black-crowned Night-Herons on both TWEETERS and OBOL
are starting to bug me. Strictly speaking, a "rookery" is a nesting
colony of birds. Although originally applied to the Rook (Corvus
frugilegus), a Eurasian species of crow that nests in colonies, the
term "rookery" is also commonly (and correctly) applied to nesting
colonies of other species that nest in trees, such as cormorants,
herons, etc. However, for herons, the specific term "heronry" is more
appropriate. Neither "rookery" nor "heronry" is correctly applied to
non-breeding congregations of birds during the winter.

What Ellen Blackstone referred to in a recent TWEETERS note is a
"roost", or more precisely, a "communal roost". A roost is any place
where a bird spends the night (or in the case of owls and night
herons, which feed at night, where they spend the day!). Though it's
correct to describe an individual bird's sleeping place as a roost,
the term "roost" is applied more often to communal roosts, which can
involve anything from 5 or 10 birds (as is common with night-herons)
to many thousands, as in European Starlings, crows, or gulls.

It is misleading to refer to a wintering group of night-herons in
W. Washington or Oregon as a "rookery" because, with few exceptions,
night-herons do not nest west of the Cascades; they are present at
these roost sites only in winter.

And by the way Ellen, I believe the night heron roost on Fir
Island Road, west of the Skagit WRA headquarters, is currently active,
although I recall someone on TWEETERS saying they saw only 2 herons
there recently. Any further updates?

Wayne C. Weber
Kamloops, B.C.
wayne_weber at bc.sympatico.ca