Submission No 414: Eurasian
Hobby Falco subbuteo, West Island, Ashmore Reef 2nd November
2003 (Unpublished).
This case concerns the rather
remarkable claim of a Eurasian (Northern) Hobby seen and
photographed on West Island, Ashmore Reef (12º14’30’S/122º58’E) on the 2nd
November 2003.
The bird was described as
superficially similar to a Peregrine Falcon Falco
peregrinus. With a black hood and heavily striated breast. Dorsally the
bird appeared much lighter than the more familiar Peregrine Falcon from
Australia and the striations below much heavier and this led the observer and his advisers(s)
to explore other possibilities. The black ‘teardrop’ through the eye, buff
white forehead and nape with yellow legs and cere, provided an unfamiliar
appearance. Size estimation was difficult with no point of reference but was
considered to be at least 30 – 40cm in length. The combination of these
features, close examination of the photographs and consultation with local
raptor experts concluded (using process of elimination, rather than descriptive
data) that the
bird was most likely a Eurasian (Northern) Hobby. The ill-defined head
pattern, scalloped upperparts, and the dense, dark, streaking on the
underparts, indicate that it is was a
juvenile.
Round one looked positive
with six members voting in favour of acceptance and two against.,
aAfter all not many falcon species feature a
dark moustachial stripe and heavily streaked underparts and Eurasian (Northern)
Hobby appeared to be the only reasonable candidate. However, one of the desentingdissenting
members decided to seek expert opinion from Dick Forsman from Finland to help
with his deliberations and to quote direct from his expert opinonopinion:
“Peregrines do
not have to be heavy-looking, and this applies especially to juveniles
(males?). I do not see this individual as any different from a lot of
first-winter birds. Anyway, size is always difficult to judge from photographs
and even if the average measurements of different subspecies differ the
variation in measurements between different individuals shows a great deal of
overlap… The bird also appears to have a rather heavy and bulbous bill perhaps
more typical of a smallish Peregrine Falcon. Both Northern Hobby and Eleonora's
Falcon have relatively small and finer bills.”
FollowupFollow-up
communication then expanded on some of the facts, which further supported
Peregrine Falcon and ruled out other species such as Eleonora’s Falcon F. eleonorae. This revelation
caused members that voted in favour, including a number of Australian experts
to rethink their views. The second round resulted in a unanimous non-acceptance
with most members now favouring Peregrine Falcon most likely a Juvenile male of
the migratory northern race calidus (or even a faded japonensis as
suggested by one member).
Interestingly, Eurasian Hobby has been reported in
Australia before
but the claim has not been assessed by BARC. The following is an entry in
the appendix in Johnstone & Storr (1998). ‘Eurasian Hobby Falco subbuteo One unconfirmed
record. Single bird tentatively identified as this species by J. Darnell
observed between Scott Reef and Rowley Shoals at 15º20’S 120º43’E on 25
November 1997. The bird was in sub-adult or first winter plumage. Breeding in north-westnorthwest
Africa, Europe and Asia and migrating south in winter. Vagrant to Java and
Timor.’
The
Peregrine subspecies calidus is known
to winter in the Wallacean region (e.g. Timor, and possibly Sumba and the,
Moluccas) according to, White &
Bruce (1986) Birds of Wallacea. BOU Checklist.
· Clements,
J.F. (1991), Birds of the World: a Check
List, Ibis, Vista, CA.
· Coates,
B.J., Bishop, K.D. & Gardner, D. (1997), A Guide to the Birds of Wallacea, Dove, Alderley, Queensland.
· Cramp,
S. (1980), The Birds of the Western
Palearctic, Vol. 2, Hawks to Bustards,
Oxford University Press, Oxford.
·
Forsman (1999a) Identification of Eleonora’s
Falcon. Alula 4: 122-126.
·
Forsman (1999b) The
Raptors of Europe and the Middle East. Poyser, London.
· Grimmett,
R., Inskipp, C. & Inskipp, T. (1998), Birds
of the Indian Subcontinent, Christopher Helm, London.
· Iozawa,
H., Yamagata, N. & Yoshino, T. (2000), Japanese
Bird 550: Landbirds, Bunichi General Publisher, Tokyo (in Japanese).
· Kanouchi,
T., Abe, N. & Ueda, H. (1998), Wild
Birds of Japan, Yama-Kei, Tokyo (in Japanese).
·
Johnstone, R.E. & Storr, G.M. (1998), Handbook of Western Australian Birds, Vol. 1
– Non- passerines (Emu to Dollarbird), Western Australian Museum, Perth (p.
346).
· Lekagul,
B. & Round, P.D. (1991), A Guide to
the Birds of Thailand, Saha Karn Bhaet, Bangkok.
·
MacKinnon, J. & Phillipps, K. (1993), A Field Guide to the Birds of Borneo,
Sumatra, Java and Bali, Oxford University Press, Oxford.
·
Marchant, S. & Higgins, P.J. (Eds.) (1993), Handbook of Australian, New Zealand &
Antarctic Birds Vol. 2, Raptors to Lapwings, Oxford, Melbourne.
·
Mullarney,
K., Svensson, L., Zetterstrom, D. and Grant, P. (1999) Collins Bird Guide: The
most complete field guide to the birds of Britain and Europe. Collins, London.
· Robson,
C. (2000), A Field Guide to the Birds of
South-East Asia, New Holland, London.
·
Sibley, C. & Monroe, B. (1990), Distribution and Taxonomy of Birds of the
World, Yale Uni. Press, New Haven.
·
Wild Bird Society of Japan (1982), A Field Guide to the Birds of Japan,
Wild Bird Society of Japan, Tokyo.
·
White
& Bruce (1986) Birds of Wallacea. BOU Checklist.
Appendix
1
SIZE
and BUILD
Immediate impression is that this bird is relatively lightly built. This is perhaps the most likely reason to rule out Peregrine Falcon at an early stage in the identification process. To my mind it appears to be a smaller rather than larger bird, but then I’ve never seen a northern hemisphere Peregrine Falcon and have limited experience with juveniles (of any sex) in Australia. There is however a photograph in Forsman (1999b) that, with the exception of slightly heavier tarsus and feet, appears structurally very similar to the Ashmore bird….but I’m still uncertain!
Dick
statesstates, “Peregrines do not have to be heavy-looking,
and this applies especially to juveniles (males?). I do not see this individual
as any different from a lot of first-winter birds. Anyway, size is always
difficult to judge from photographs and even if the average measurements of
different subspecies differ the variation in measurements between different
individuals shows a great deal of overlap… The bird also appears to have a rather
heavy and bulbous bill perhaps more typical of a smallish Peregrine Falcon.
Both Northern Hobby and Eleonora's Falcon have relatively small and finer
bills.”
HEAD
PATTERN
The bird does not show the double peak that one would expect of Northern Hobby rather it is single rather rounded cheek patch (most obvious in “hobby4_1”). This seems to be at variance with all recently published sources that I can lay my hands on for Northern Hobby.
In contrast Juvenile Eleonora's Falcon seems be more variable in this feature and may or may not (usually not it seems) show a double peaked cheek (e.g. Mullarney et al. 1999, Forsman 1999a, 1999b, Ferguson-Lees and Christie 2001).
The open and rather rounded cheek patch also seems entirely consistent with Peregrine Falcon.
Dick states; “The cheek of Northern Hobby always shows the double peak and the moustache mark is finer/narrower and sharply POINTED at the tip (than the Ashmore bird). Northern Hobby also shows two pale spots on the hind neck, not a line down the nape as larger falcons do.”
“Eleonora's Falcon lacks the
double peak in the cheek patch and in that regard is consistent with the
Ashmore bird. However, it does not show the pale line down the nape. It may
show (or may lack) Northern Hobby-like spots lower down. Eleonora's Falcon also
has a narrow and sharply pointed moustache, much like Northern Hobby (and thus unlike the Ashmore
bird).”
First winter Peregrine Falcon shows a blunter-ended and more rounded moustache.
In
summary, on head pattern the Ashmore bird is not a Northern Hobby or Eleonora’s
Falcon. Characters visible are however consistent with a Peregrine Falcon
(especially the cheek pattern and the Peregrine-like rounded tip to its
moustache).
UNDER
BODY STREAKING
The fine streaking on the breast seems to eliminate Northern Hobby. All juveniles pictured in Forsman (1999b) (3 different individuals) and all other photographs that I can find show juvenile Northern Hobby to have relatively broad (heavy) dark brown or black streaks that are not dissimilar to adults of that species. The plate in Ferguson-Lees and Christie (2001) does seem more similar to the Ashmore bird than any photographs I have viewed in that it shows streaking on the juvenile Northern Hobby to be considerably finer than that of the adult. However, strangely in the text of the same book Ferguson-Lees and Christie state for juvenile “much as adult below, if tending to be more heavily streaked…” which is almost the direct opposite of the plate! Given photographs and statements in other text are entirely consistent with this statement I can only conclude the plate is in error.
The
streaking is however more consistent with Eleonora's Falcon. For example in
discussing identification of juvenile Eleonora's Falcon Forsman (1999a) states
'The streaking of the breast is mostly finer than in (Northern) Hobby changing
to Peregrine-like arrowheads towards the flanks'. In that regard the breast of
the Ashmore bird does not seem to differ greatly from that expected in an
Eleonora's Falcon.
Dick states “For Eleonora’s Falcon the underparts streaking can be similar in the two species and is not diagnostic in this case.
The streaking on the breast
is too fine for juvenile Northern Hobby. N Hobby also never shows this
combination of very fine streaking on the breast that changes to heavy blotchy
streaks on the flanks.
The streaking below of first-winter Northern Hobby is always BLACK (very dark brown), the streaks are broader forming fewer vertical lines across the breast compared to this bird. Hobbies can show broader streaks towards the flanks, but in my experience NOT the rounded spots typical of Peregrine.”
I can’t find images of
Peregrine Falcons that are an exact match when it comes to streaking, but bear
in mind that Dick thinks this is a Peregrine Falcon of the race calidus and most images are of the more readily encountered
European form peregrinus. The single
image of a “calidus-type” juvenile that
I can find (inverted commas in the text suggest the identification is not
certain) (Forsman 1999b) does show fine streaking on the upper breast much like
the Ashmore bird. However, unlike the Ashmore bird these streaks develop into
blunt arrowheads on the lower breast of this bird, even in the center of the
breast. This bird also looks considerably heavier than the Ashmore bird so
perhaps it’s a female?
COLORATION OF UNDER PARTS
Not a lot here as the
colour of the streaks is discussed above. My impressions from plates and
photographs is that juvenile Northern Hobby are usually more buff rather than
cream or whitish on the ventral surfaces than the Ashmore bird. Indeed some
photographs (e.g. Forsman 1999b) show a very warm shade of rich buff across the
ventral surface of juvenile Northern Hobby. Admittedly, the photographs in the
submission must surely be slightly over exposed given their apparent
brightness…but still the bird seems to be too pale for a Northern Hobby. As
there is a pale form of Eleonora’s Falcon this feature could be consistent with
either an Eleonora’s Falcon or a pale race of the Peregrine (e.g. calidus).
COLORATION
OF UPPER PARTS
The
Ashmore bird shows rich almost chestnut brown fringes and darker sooty
brown-grey centers to feathers of the dorsum. All the texts I have suggest
Northern Hobby has finer more buff-coloured fringes and darker grey centers to
feathers in this area when compared with the Ashmore bird. In contrast, the
Ashmore bird’s dorsal colouration again appears to be consistent with that of a
juvenile Peregrine Falcon.
Dick states; Juveniles of both Eleonora’s Falcon and Northern Hobby are darker/blacker above and have buffish, not rufous fringes to the coverts when compared with the Ashmore bird.
RUFOUS
of LOWER FLANK and THIGH
There
is a trace of rufous on the lower flank and thigh. I have been unable to find
anything that suggests this is significant in the identification of Northern
Hobby, Eleonora’s Falcon and Peregrine Falcon. I have also viewed images of all
three species that show traces of this. Thus, although mentioned in the
submission I don’t think it is of any great significance.
Dick states: I do not know that this would be of any importance.
In
conclusion I’m reasonably satisfied that this is not a Northern Hobby. There
also seems to be a couple of key characters that eliminate Eleonora’s Falcon
(namely dorsal colouration and the bluntness of the moustache). With that in
mind it seems that Peregrine Falcon is a reasonable conclusion. I’m not
entirely comfortable with the bird’s structure but in this case will defer to
Dick’s expert opinion that Peregrine Falcon can indeed appear this finely
built.
Finally on race I haven’t been able to find that much on calidus and thus don’t believe I’m in a position to draw any conclusions. However, Dick states “The distinctly brown upperparts are good for calidus in my opinion, and e.g. in Europe the local non-migratory subspecies are darker above than calidus at any given date.”
Verdict: Not Accepted
Tony Palliser
Chairman, Birds Australia Rarities Committee
Comments second round:
I have found this a very difficult case and have
done much literature research and sought advice from many sources. I had
intended that this would be a long dissertation on my findings, reasons for and
against, but now intend to keep it fairly brief. I have found the Ferguson-Lees
& Christie Raptors ID book very disappointing and unhelpful. It is not the
panacea I had hoped. There is no illustration of the migratory Peregrine F.
p. calidus which some claim
this bird to be. It states that moustachial stripes are narrower but doesn’t indicate
just how narrow. MacKinnon & Phillipps do have an illustration and I
concede that from that illustration the head at least could fit the Ashmore
bird even though the observer said that it was not a Peregrine. I’m also
worried by the cheek pattern which doesn’t fit Hobby in lacking the ‘earcovert
notch. John Darnell, a very experienced field observer in the Asian region and
museum worker remains adamant that it is a
E. Hobby as does Stephen
Debus. But my Japanese and European consultants are less convinced. So as I
think we need more certainty for a first for Australia, I now say wait for a better
documented report before including this as an Australian
bird. I remain unconvinced that it was a Peregrine, reasons given below along
with some now probably irrelevant other thoughts.
Six
in favour, two against! As one of the main protagonists in favour, I’ll just
deal with those against.
Whilst considering the record ‘highly
probable’, John Hatch wasn’t quite convinced so teetered on the conservative side
and voted against. Like me, and apparently the rest of us including Rohan, he
dismissed Peregrine on the grounds of bulk. Perhaps I can persuade him to
change his mind in a third round. I consider a third round obligatory in cases
like this.
Initially, Rohan Clarke thought it possibly an
Eleonora’s Falcon, an even more slender, longer winged, longer tailed species
than Eurasian Hobby. In attempting to rule this out, he sought ‘expert’ advice.
To his surprise, the ‘expert’ went for a proportionately shorter winged,
shorter tailed, and heavier bird, a Peregrine no less. I find this assertion
staggering.
There is
nothing in the size, shape or structure of the bird to suggest Peregrine,
especially of the largest, heaviest race, calidus
as suggested.
Apart from
the fact that the observers considered, then ruled out Peregrine, it is not a
Peregrine for the following reasons. I’ll deal with structural features first
as these are less variable, more reliable than plumage.
1. It is too
small.
2. It is too slightly built. Peregrines nest at
the end of my road. Thus I’m extremely familiar with both adults and juveniles.
They are robust, powerful birds. They never look like this.
3. The tarsi
and talons are too weak.
4. The tarsi
are too long and too exposed. The tarsi of Peregrines are wholly or partly
hidden by the full and luxurious thigh feathering, (trousers) of that species.
Using the dimensions for juveniles in BWP, I calculate that compared to the
wings and tail, the tarsi of E. Hobby are 13% longer than that of Peregrine.
This is a substantial amount especially for a species that already has
proportionately longer wings and tail.
5. In a
perched Peregrine, the tips of wings fall well short of the tip of the tail. In
this individual, as in Eurasian Hobby, they are roughly equal in length.
Regarding the
plumage, according to all the reference material in my possession, the plain
unmarked rear flank and ventral area fits E. Hobby and should disqualify
juvenile Peregrine, which is always streaked or barred in that area.