Tweets,

Yes, thanks Michael for the insightful confirmation that I have
repeatedly mispronounced Vaux's Swift:( That's what I like about this
list, and birding, is that one can continually improve one's knowledge
in our particular interest).

My son and I were at the Iona Sewage treatment ponds on Sunday, June 22
and saw what we perceived to be a mixed flock of Vaux's and Black
Swifts, as well as a single large flock (25+) of only Vaux's Swifts.

At the ponds on Monday June 23, we noted several BLSW, kept relatively
low down by the low cloud cover.

It is interesting to confirm that these birds do mix together.

The field guides that we use, describe the VASW as a bird with no
apparent tail, "cigar-like", with some lighter colouration of the breast
area. And the BLSW as a larger bird with a sometime apparent notch in
the comparatively larger tail.

Are there any other field marks that we should be aware of? Is there
any variation to the flight pattern? Does VASW tend to *twinkle* its
wings more so than BLSW, etc?

Ken Klimko
Richmond, BC