Hi Mike,
I must admit I found Jim Tate's original posting interesting but somewhat
open to interpretation.
The only "big" tern with a red bill (in any stage of plumage) likely to be
seen on the Brisbane that I can think of is the Caspian Tern.
I imagine that it would be possible to see Whiskered terns on the Brisbane
river at some time of the year but they are obviously small at half the size
of the Caspian Tern.
If there was two species of terns with red bills being seen and they were so
different in size I would have thought that would have been mentioned.
However, Jim seemed to be saying that the red-billed terns he was seeing
were all large terns similar in size to Caspian Tern or, possibly, Crested
Tern.
I have recently seen Crested terns (still a large tern but smaller than
Caspian Tern while obviously larger than Whiskered and Common Terns) in my
area with bill colours ranging from lime-green to bright-ish orange-yellow
but I have never seen a Crested Tern with a bill colour I would call 'red'.
So I was intrigued by the possible suggestion that there might have been two
different species of "big enough" terns (but noticeably different in size)
both with red bills.
When I read Jim's comment I assumed he was seeing Caspian Tern, very large
with red bill, and Crested Tern, a little smaller but with 'yellow' bill.
The fact that only the "dark red" bills were mentioned does have me
wondering, though.
I would classify Common Terns and Whiskered Tern as not simply "smaller" but
"much smaller" than both Caspian and Crested Terns.
Jim said "Many of them [the terns observed on the river] appear to have dark
red bills and look big enough to be Caspians or Crested."
Jim also said "But some are smaller - are these Commons?".
I wasn't sure if Jim meant that only the "big enough" terns had red bills or
if the "smaller" terns also had red bills. I would classify Common (and
Whiskered) Terns as 'small' terns being very much smaller than Caspian Tern
and obviously smaller than Crested Tern.
Jim, by saying "Many of them appear to have dark red bills" appeared to me
to be indicating that some of the other terns had bill colours other than
"red" but what those colours were is not clear. I assumed that "smaller"
meant noticeably smaller but not "small" - as in the size of Common or
Whiskered Tern.
It did cross my mind that there could also have been Gull-billed Terns
(smaller than Crested and larger than Common) there as well; I saw one
Gull-billed Tern (with full black-cap) fly over at Woorim when I was
photographing those Common Terns the other day so they are around here at
the moment. Of course, Gull-billed Terns have black bills so that wasn't the
red-billed species Jim was seeing even if it is a "smaller" species of tern.
As you said, the Common Terns in my photographs have "dark" bills as would
be expected but some do have a reddish tinge. That is fairly common and does
cause some confusion for many birdwatchers who are expecting to see only
completely black bills on the Common Terns we get here. However, none of the
Common terns I have ever seen in SE Queensland have had "dark red" bills as
described by Jim. I assumed he was talking about the "deep red" colour that
Caspian Tern bills can be in breeding plumage stage.
I am not aware of any sightings recently of Whiskered Terns on the Brisbane
River as I don't visit there and I don't keep tabs on sightings from that
area.
Other observers from that area might be able to provide that information.
I have not heard of any positive sightings of Whiskered Terns in SE
Queensland this year so far but not all sightings are publically reported,
unfortunately.
All of the above is not a lot of help in identifying Jim Tate's terns but
the discussion is interesting and it is to be hoped that Jim's query has
prompted some Brisbane bird observers who commute on the Brisbane River to
check out the terns that are around there at the moment. It would also be
'nice' if those observations could be communicated to BirdingAus as well.
Bob Inglis
Sandstone Point
Qld
-----Original Message-----
From: Mike Carter
Sent: Tuesday, July 10, 2012 10:16 PM
To: Robert Inglis ; Birding-Aus
Cc: Paul Walbridge ; Brian Russell ; Jeff Davies
Subject: Re: [Birding-Aus] Brisbane River terns & Common Terns at Woorim,
Bribie Island,SE Qld - photos.
Thanks for this Bob, a very valuable set of shots of this little known stage
in Common Tern moult. If you have others in flight with more open wings I'd
like to see them even if of lesser quality.
But your gallery doesn't help resolve the matter of the ID of the red-billed
terns on the Brisbane River. All your birds had dark bills as I'm sure most
of us would expect in Commic type Terns in Australia in July. As Dimitris
Bertzeletos points in the preceding post, red-billed Common Terns would be
unusual. I wondered whether they might be Whiskered Terns. Are there any
around Brisbane at the moment?
Mike Carter
30 Canadian Bay Road
Mount Eliza VIC 3930
Tel (03) 9787 7136
|
