Posts Tagged ‘Snowy Owl’

Snowy Owls 2017

December 14, 2017

(Click on images for larger, hi-res versions)
Arriving back from Mexico, it was evident there was an incursion of Snowy Owls Into CT. A widespread arrival across the Mid West had hinted at an irruption year and several birds were found at Long Beach in Stratford – a typical “go to” spot for this species.
Alex and I took a ride down and immediately found a bird sat on one of the closest jetties giving great looks in the scope and decent photo opps. (A dark, female- type bird had accompanied this bird but had been flushed twice by a woman with a point and shoot camera. Grrrr!)
A week later, with continued reports of multiple individuals, I made a predawn assault and obtained some decent shots of both individuals. The birds attracted a lot of attention!
 
Studies by Josephson (1980) and others (see below) have outlined the difficulties in ageing and sexing Snowy Owls. Birds after their first year are in first Adult plumage.  According to studies of known returning birds, it may take four-five years for an adult to reach a definitive basic plumage.
Ageing and sexing Snowy Owls is clearly difficult. In December, First-year (first-basic) males and adult females can overlap in plumage but first-year (first-basic) females are often the darkest and adult males the lightest. However, while that simplistic general wisdom may hold for many birds, some known-aged females never got darker with age, while some known-aged females became as white as older adult males –  clearly field sexing will lead to some mistakes!
Even I had published a note on ageing and sexing them based on a bird seen in Lincolnshire, UK in 1991 (Hough, 1992). In hindsight, and with a lot more Snowies under my belt, that note was perhaps a little simplistic in dealing with ageing and sexing…it is way more complicated than I could ever have known at that time.
While many individual birds won’t be able to be confidently aged and sexed in the field, studies done on the breeding grounds (Seidensticker et. al) and of museum skins hint at certain helpful criteria to focus on:
  • vermiculations on the scapulars, primary tips, and inner greater coverts.
  • barring on the nape
  • presence of barring or spotting on the inner secondaries
  • number of tail bars
  • any molt contrast in the primaries
  • density of barring on the upperparts and crissum
While it is clear that field views may not provide accurate clues to age and sex, some birds can present with enough features that a good guesstimate of age and sex can be attempted.
First-basic birds sport primaries and secondaries of the same generation and have relatively pointed primaries. Tail is similar, though many of these young birds can show growth bars that while visible in the hand, are not visible under normal field conditions. Males generally show spot-like markings on the secondaries that do not touch the rachi, while females tend to show more bar-like markings, often broader and blacker. Males show 2-3 broken tail bars while females typically average more, usually 3-6.

Apparent first-basic male Snowy Owl, Stratford, CT, Dec 2017

Apparent first-basic male Snowy Owl, Stratford, CT, Dec 2017 (same bird as above). a) Pointed primaries with slight mottling; b) three tail bars; c)brownish mottling on tertials and spot -like markings on secondaries.

To summarize, while the darkest, heavily marked birds are likely to be first-basic females, first-basic males can be variable, being dark first-years or light first-year birds. These birds typically have mottling in the scapulars, tertials, greater coverts, and between the bars on the primaries, that will help separate them from adults.
However, some first-year birds may show reduced mottling – a lack of such markings may not indicate that the bird is necessarily an adult.

Apparent first-basic male Snowy Owl, Stratford, CT, Dec 2017 (same bird as above). A rather pale bird, with unmarked nape, narrow barring on underparts, rather extensive white bib (compared to female). Mottling on rearmost scapulars, tertials and primaries suggest a first-basic bird.

I’ve included a few pictures of the recent birds, and past birds from neighboring states that may be helpful. The captions hone in on certain aspects of plumage that may hint at age and sex, but these are by no means definitive and I welcome comments on anything here that is incorrect. Again, these are just suggestions based on the current literature.
 

Apparent first-basic female Snowy Owl, Stratford, CT, Dec 2017. Larger size, typical of females was apparent in the field. Very heavily barred with reduced white bib, brown mottling on tertials and heavily barred nape. Barring extending onto the vent is also typical of females, especially first-basic individuals.

Apparent first-basic female, Stratford, Dec 2008. Note a)densely barred nape; b)extensive mottling on greater coverts, tertials and some rear scapulars;c) bar-like markings on secondaries; and d) 5 tail bars, with barring extending across both vanes.

Apparent first-basic female, Stratford, Dec 2008. (same bird as above).

First-basic Snowy Owls retain their primaries, tertials and tail until the early summer when they are essentially one year old. By the time we see these birds in Nov/December, they will be second-basic plumage having completed or nearly completed their first primary moult (usually starting with p7). Older birds (e.g.,third-basic) subsequently follow the same molt schedule with p7 being one of the first to be replaced.
So, how do you know in December, if the bird is a first-basic or older? Looking for visible signs of a first-year (see above) and then examining the primaries to see if there is any molt contrast between new, replaced primaries (typically p7) and secondaries. Apparently the differences are subtle, but possible on good close up images of the wing. Also, the newer primary tips often show a more rounded shape with a wider, white terminal fringe.)

Apparent first-basic male Snowy Owl, NY, December 2008. a) Pointed primaries with dark bars reaching to tip; b) spot-like markings on secondaries; and c) three narrow tail bars, Also, shows a noticeable white bib and unmarked vent, further pointers towards a male.

The following references conatin a wealth of information, but as Snowies seemed to be still showing up, hopefully this will help point people in the right direction if they are interested in trying to age/sex birds.

References

Cramp, S. (ed.) 1985. Handbook of the Birds of Europe, the Middle East and North Africa, The Birds of the Western Palearctic, Volume 4 – Terns to Woodpeckers. Oxford University Press.

Hough, J. 1992. Snowy Owl plumages. Birding World 5(3): 96-97.

Josephson, B. 1980. Aging and sexing Snowy Owls. Journal of Field Ornithology 51: 149-160.

McGowan, K.J. 2001. Snowy Owls (Nyctea scandiaca): some recent visitors and thoughts on aging and sexing [online]. Available from: http://www.birds.cornell.edu/crows/snowy.htm [Accessed December 2009].

Pyle, P. 1997. Identification guide to North American birds – part 1. Slate Creek Press, Bolinas CA. 

Sangster, G., Collinson, J.M., Knox, A.G., Parkin, D.T. & Svensson, L. 2004. Taxonomic recommendations for British birds: second report. Ibis 146: 153-157.

Witherby, H.F., Jourdain, F.C.R., Ticehurst, N.F. & Tucker, B.W. 1952. The Handbook of British Birds, Volume 2. H.F. & G. Witherby Ltd., London.

 Mathew T. Seidensticker, Denver W. Holt, Jennifer Detienne, Sandra Talbot, and Kathy Gray. 2011. Sexing Young Snowy Owls. Journal of Raptor Research 45(4):281-289. 2011  https://doi.org/10.3356/JRR-11-02.1

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Gulls Gone Wild!

April 20, 2015

17th-19th April – West Haven, CT (click images for larger view)

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First-cycle Thayer’s Gull, West Haven, CT 19th April

After Nick Bonomo refound the adult Kamchatka Gull at Oyster River on the West Haven, Milford border, (first found in Southport, CT by Mayn Hipp and Mike Warner a week previously), Oyster River had been given a good going over by a few locals, mainly because it was a great loafing spot for gulls and hosted CT’s only Ross’s Gull in the 80s.

The birds are frequently disturbed here by Joe Public and when flushed, frustratingly often fly off into the sound and despite checking the area, the Kamchatka Gull had not been seen since. Nick and I did find a surprisingly late Snowy Owl along the same stretch of coast. Later that night, amazingly enough, Keith Mueller, birding the same spot an hour before Nick refound the Kamchatka, had unwittingly photographed another Mew Gull while taking shots of Bonaparte’s Gulls. The images appear to show the Eurasian race of Mew Gull, known as Common Gull.

On Friday 17th, I had left work early for a Dentist appt. Deciding to head down to Oyster River on spec, I was just leaving New Haven, when Nick called to tell me Keith had relocated the Kamchatka Gull back at Oyster River. Panicking, I set off only to hit rush hour traffic. Halfway there I got a call that the bird was flushed by a clammer and was not on view. AAARRRGGGHHHH!!! Relief came when Keith called back and said he had it out on the flats. A mad sprint later and the bird showed excellent roosting on the flats.

Adult Kamchatka Gull, Oyster River, CT

Adult Kamchatka Gull, Oyster River, CT

I spent Sunday afternoon 19th April birding, but  there was no sign of the Kamchatka Gull or any other gulls for that matter. Taking my usual route back to the house, I stopped at the West Haven boat ramp, as I often do to check out any gulls. There were few birds in evidence but I did spot a first-cycle Iceland Gull on the water.

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_P9A4672After shooting it for some time, I left. As I was reversing back, I caught a glimpse of a bird landing below the dock, but the metal barricade obscured everything but the underside of the wingtip. It looked surprisingly silvery, but didn’t strike me as Iceland. My spidey sense was tingling, so I stopped the car, got my bins and peered over the barrier to find a first-cycle Thayer’s Gull staring back at me. Holy !!!@@$$$$.

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Doing a double-take, I checked off the short primaries with nice silvery fringes, brown, pale-tipped tail and overall bleached, cafe-au-lait plumage. Structurally it was all thayeri with short legs, a slight pot-belly and a disproportionately small, but pear-shaped head. The bill was mostly dark, just beginning to get some flesh-color at the base. Thayer’s retain their juvenile mantle feathers until later in the winter and upperparts seemed to be all worn first generation feathers, again supportive of Thayer’s Gull.

_P9A4882In flight, coffee-coloured (not blackish, or dark brown) tail, secondary bar and outer webs to the outer primaries all screamed..RESULT!!

_P9A4778Nice pale underside to primaries, here the light showing through illuminating the “venetian blind” effect on the primaries.

_P9A4845Note color of primaries and tertial centres being rather uniform and not contrastingly darker as some of the similar, bleached Herring Gulls nearby. What a cracking bird! I’ve always dreamed of finding something like a Mew Gull or a Franklin’s Gull here, but Thayer’s was not really on my radar.

A fantastic few days of birding on my local beaches!

_P9A4254Snowy Owl, Bradley Point, West Haven..a nice consolation for missing the Kamchatka Gull on the first evening.

Land of Ice and Snow

February 9, 2014

A quick morning’s birding around Stratford and Milford over the weekend, yielded two-three Snowy Owls and a few Rough-legged Hawks. Great looks at the Snowies, including one being harassed by a Northern Harrier and adopting it’s defensive posture with wings splayed wide open.

_MG_6015Several close Rough-legged’s allowed good looks, including a smashing dark-morph bird that I chased down in the car by Sikorsky Airport. From a European perspective, Rough-legged Buzzards, as they are known across the pond, don’t occur in this dark morph. Stunning birds! _MG_5901A few years back, while birding on Plum Island, Mass, I came across this really tame dark morph Rough-legged which showed brilliantly hunting rodents right in front of us!

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