g'Day all
Some might remember late last year when I posted my observation of a
solitary Black Tern (Chlidonias niger) in non breeding plumage sighted
at Stieglitz Tas. on 18/11/2014. Having unsuccessfully searched
suitable habitat areas around the district many times over the past 3
months and also waiting hopefully for some other observer to turn it up
somewhere else in Tassie, it looks like that is not going to happen.
In the meantime, I have prepared a MS Word Document file that describes
the observation and will send it to any one that wants it and also have
decided to post this on birding aus, just for the record.
The observation is described below.
regards
Ian May
PO Box 110
St Helens, Tas. 7216
------------------------------------------------------------------------
Black Tern sighted at Windmill Swamp, Stieglitz. Tasmania 7216 Australia
at approx. 1530 on Tuesday 18 November 2014. Ian May PO Box 110 St
Helens 7216
At about 1530 on Tuesday 18 November 2014, I was exercising my dog at
the freshwater "Windmill Swamp", Stieglitz Tasmania. 7216. (41 19.75
S, 148 18.75 E) when I observed a small/medium marsh type tern, flying
around the reedy north eastern margins of the lagoon about 200 meters
from my location. Watching this bird for about 1/2 an hour from
distances of between 300 to less than 10 meters, it appeared systematic
in its intent to cover the feeding area as it was slowly moving in an
anticlockwise direction around the margin of the lagoon until eventually
passing directly over me standing among reeds at the north western edge
of the swamp It continued flying feeding, moving to the south of me
along the western margin to SW of swamp before ascending as described
below and departing towards Jocks Lagoon. The bird was observed with 10
x 50 binoculars in good light conditions with sun behind me and in
reasonable weather conditions, partly cloudy, moderately calm to ENE <
10 knots with estimated air temperature 18-20C. I did not have a camera
with me and no photos were taken.
Description
Underparts extending to under tail, sides of neck, collar, throat and
forehead white. Underwing grey. Black crown, faintly speckled
adjacent to forehead. Black extending back from just forward of dark
eye, across crown towards nape and also vertically down side of face as
an oblong shape sideburn from behind the eye. The shape of this marking
on the side of the face resembled a curved T shaped jigsaw piece.
Adjacent to and forward from the bottom of the T, there was a dark mark
loosely resembling a small heart shaped eye patch separated by a
conspicuous pale 1/2 eye ring especially behind, above and below eye.
Back was grey, slightly darker at mantle, darker than tops of wings with
maybe the faintest brownish tinge visible at certain angles. The
contrasting white between the back and crown formed a conspicuous white
collar. Top its wings, light grey but darker on leading edge from
carpel to body, more pronounced towards body but paler along wing centres.
Conspicuous dark grey triangular shaped mark extending down and well
into white sides of breast from front of wing, more pronounced than a
smudge. It had a paler rump, darker towards its light grey tail and
slightly darker again towards tip but no visible bar. Tail was slightly
forked but more squarish when spread. Underwing was pale but darker
towards rear. Conspicuous white collar between black crown and grey
back. Legs and bill appeared grey/black. Bill was longish, slightly
down curved; appearance accentuated while pointed downwards when bird
flying in horizontal position before swooping down to catch insects. No
calls heard.
Flight Behaviour
Buoyant, erratic, characteristic darting, swooping, back tracking,
diving, over marshy reeds and rushes, not flying over open water. Rapid
short wing beats, very short periods hovering. Unusual flight
characteristic when departing swamp, ascending and circling rapidly
(Circles in diameter of about 30meters) and in what almost appeared to
be a small thermal column to an estimated 150 m drifting south, (then
flying directly south for about 1 km and then descending on next known
body of fresh water at "Jocks Lagoon" RAMSAR site. it appeared to use
its elevation to help locate the next new area). No further
sighting. I had no camera with me at the time,
Feeding behaviour
This bird appeared to be feeding on insects or tadpoles, picking from
water surface amongst vegetation, possibly catching small insects above
water. Preference to fly and feed over reedy, marshy vegetation rather
than open water or drier tussock grasses. (Abundant marshy, broad
succulent <1m rushes/ reeds). It was continually darting and diving
into small water areas (estimated 3-4sq m) mostly encircled by these
vigorously growing rushes.
Discussion
Windmill Swamp is a fresh water lagoon.
Particularly its distinctive buoyant, very erratic flight/feeding, its
body shape and Jizz, and its habit preferring to fly above reedy margin
than over adjacent open water were all distinctive characteristics that
first alerted me to this bird as different from Whiskered and
White-winged Black Terns, species that I have had many years experience.
My impressions compared to non breeding plumage, Whiskered Tern and
White-winged Black Tern; this Black Tern was slimmer, sleeker build
possibly smaller body. Because of distinctive jizz and flight
behaviour, its unique face marks, a conspicuous partial eye ring, the
highly contrasting white collar between dark crown and mantle, dark
marks on sides of breast, slightly down curved longish bill and slightly
forked tail, I would consider this bird easier to ID compared to
separating non breeding and juvenile White-winged Black Tern from
Whiskered Tern.
------------------------------------------------------------------------
Ian May wrote:
g'Day all
At about 3.30pm on Tuesday afternoon (18/11/2014) while exercising my
dog at Windmill Swamp, Stieglitz Tas. I observed a solitary Black Tern
(Chlidonias niger) in non breeding plumage, feeding vigorously around
the vegetated rushy, reedy margins of the fresh water swamp. After
about 1/2 an hour, the bird ceased feeding and began circling rapidly,
ascending to an estimated 150 meters height where it then flew south
for as long as I could watch it holding my binoculars and to where it
was just a speck in the sky, almost out of sight it then descended out
of sight towards Jocks Lagoon also fresh water. (RAMSAR site), about 1
km away from where I was standing.
Most distinctive feature from distance is its buoyant and erratic,
flitting, darting flight. Its direction changes were remarkable to
watch, rapidly swooping, back flitting and diving from about 10 meters
to the water surface among reedy vegetation feeding on what appeared
to be surface insects. Unique face markings, dark marks on sides of
breast, white collar and rapid floating, buoyant, darting erratic
flight were the most characteristic features that I could see.
The next day and also today (Thursday) I was unable to relocate the
bird after searching all coastal swamps and suitable habitats from St
Helens to Falmouth. I did not have a camera with me, but 100% certain
of this bird's identity having experience with and studied both
Whiskered and White-winged Black Terns in previous years. The
purpose of this note is to alert observers in Tasmania to be on the
lookout. I will post more information in the next week with all
minor detail.
I decided to post this on Birding-Aus because for me, BA offers the
more for bird watchers, not just for twitchers and seems to have the
best, most comprehensive and reliable archive.
Good birding and best wishes
Ian May
St Helens, Tasmania
0428337956
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
|
