Friday, 24 October 2014

Toucan Tongues...and bill development

An almost embarrassing number of Collared Acararis; four ! have landed themselves in our nets in the past week of standard banding for Costa Rica Bird Observatory.  Our initial excitement has now dwindled to self-preserving musings of how best to extract and keep that snapping bill away from flesh at the same time.

We have been quite lucky to be able to closely examine a broad range of ages, from juveniles, almost surely straight out of the nest, to the beautiful adult below.

With such a run, it has been easy to observe the differences in bill development between the ages.  It is quite interesting to see and compare the development of structure, colour, and even strength, so up-close and personally. 

Adults also have far better bill-eye-hand coordination. 

Amidst requests to "take that thing off my finger, pleease" during processing, we have had many opportunities to see the amazing appendage-like tongue that is possessed by these creatures. 

Juveniles, likely not long fledged.  Note the dull colour of the bill and smoothness of the edge. 

And this feathery tongue!  Apparently used for helping push food down the throat, and loaded with taste receptors to decide whether its worth the effort or not.

This juvenile is developing bill serrations and colour, and that tongue is even more feathered.  Curving of the bill is becoming more pronounced.

The ultimate adult.  Strongly coloured bill.  Tongue is very feathered. 

Serrations are verified.

And this little guy.  Not caught in Tortuguero.  Didn't show his tongue. But Richard didn't want this to end on him being bitten. 
Emerald Toucanet, caught at Madre Selva, CRBO standard banding site in the Highlands.

~ Author Pauline Pearse (Richard's Aracari-bill opener when the bites hurt)

Wednesday, 22 October 2014

An early start for thrushes...CR style

Pauline joined me in San Jose and we are banding together until mid November...
What a start at InBIO, our standard banding site in San Jose, Tropical Kingbird. We see many every day, but never before in the hand
Yesterday our standard banding site was at our base at The Sea Turtle Conservancy, here in Tortuguero. This view of Tortuguero including four of our standard banding sites from the Cerro after a recent climb..
Here we can catch large numbers of migrants, as well as the resident species, and yesterday we were successful in banding over 70 Catharus thrushes.
Here a selection of other species caught yesterday too.
 Chestnut-sided Warbler, a regular species around the sites.
Ovenbird, we don't catch many, six in our last two visits to Costa Rica compared to 59 Northern, and four Louisiansa Waterthrushes

Streak-crowned Woodcreeper, the lowland equivalent of the Highland Spot-crowned Woodcreeper.

The final bird of yesterday, our friendly grosbeak. We catch many Rose-breasted Grosbeaks at Long Point Bird Observatory in Canada, but this is my first in Costa Rica,...
Behaviour in the hand still the same !

What a day, planned and  hoped for...but unexpected..
101 birds captured of 21 species, of which 15 species were migrants.

This followed an amazing previous day  standard banding at Parq. In particular one amazing net round....
I was vis mig counting Chimney Swifts pouring over, when Pauline appeared from the forest with three bags full !
The photos say it all...
A young Semiplumbaceous Hawk..
 and two very juvenile Collared Aracari..
Though almost certainly siblings, interesting to compare the rate of development.

Twenty days since my last notes and some highlights, mainly species not mentioned before will follow on a blog.....if not too busy at our Aeropuerto site.....
Yes !
A standard banding site at the end of the airstrip...not primary forest, but coastal woodland regenerating and can be full of migrants too..

Saturday, 11 October 2014

A First and a Second

A last-minute decision to get out of bed and put in a few hours on the Marshes between showers this morning was rewarded by a first for the Group and a first for me (though other TRG members have ringed them with other groups elsewhere) in the shape of a passing Whinchat. Also unexpected was only the second Meadow Pipit that we have ever caught on the Marshes.

This, according to Svensson, is a juvenile female
The supporting cast gracing the nets this morning, among Blue Tits so numerous that I'm trying to blank them from my memory, were a Jay, another new Kingfisher, two more new Cetti's, Blackcaps, Bullfinches, Goldfinches, Goldcrests, Long-tailed Tits, Great Tits, Wrens, a Robin, and four more new Reed Buntings recruited to our colour-ringed RAS project.

Tuesday, 30 September 2014

Costa Rica - rufous-tailed to steely-vented...

Today we were banding at InBioparque in the capital San Jose. A standard CES type site, within a park with objectives much like Regents Park in London but smaller. Migrants in evidence here, with a Canada Warbler, several Chestnut-sided and a great surprise to see a Worm-eating Warbler
The above photo of a Canada Warbler was taken at our Tortuguero site, more on banding there later...
...back to InBioparque...
I don't associate this inner city site with good I was proved wrong. Following a regular Rufous-tailed, show below..
A  new species for me, a Steely-vented Hummingbird with a different but equally stunning tail.
In some hummingbirds males perform at a lek, where tails may have a role. These two species don't lek but are very aggressive towards others. As well as the steely-tail in the photo below, note the standard wing measuring technique taught and used across the Americas...
Agustin doing the biometrics, and below with a House Wren, a wren species found in many different sub-species across North and South America.
Agustin is a local Costa Rican and we are banding together across all our sites in the coming weeks.

A final warbler from our first week's banding in Tortuguero, our Caribbean coastal base. We will return to Tortuguero in about 2 weeks after a spell at our Highland sites.
This a juvenile Mourning Warbler, a species not easy to see though apparently a common Fall migrant, we only caught two last Fall, so a pleasing start.!

Saturday, 27 September 2014

Neither Scarlet nor Common

This splendidly chubby juvenile Rosefinch turned up in our nets on the Teifi Marshes reserve this morning, much to the surprise and delight of all present. With a fat score of 6 (that's fat), and having gorged itself on blackberries, it seemed ready to carry on South without much delay.

A busy morning also produced good numbers of Blackcaps and Chiffchaffs, another new Kingfisher, two lingering juvenile Reed Warblers ringed elsewhere on the reserve several weeks ago and both still in post-juvenile moult, as well as the expected selection of regular residents.

Friday, 26 September 2014

Back from Dream Island

Time now for an update, having spent the last few days catching up on much needed sleep after a week on Skokholm, falling into bed after midnight and rising again at 6am.

Time for the first net-round
Most of the time the weather was unseasonably fine and sunny, with a steady breeze from the South-east, with one day when it switched around from the North and was more blustery with a few showers.

There was a steady flow of migrants, with the day after the northerly producing a large arrival of Chiffchaffs. As well as the mist nets and Heligoland traps, we used spring traps, potter traps and 2-shelf nets, these producing pipits and Wheatear - two of which were fine adult male Greenlands. We tried everything we could think of (including a dead mouse and other even less salubrious lures) to entice one of the calling Water Rails, but predictably perhaps this was to no avail.

Star bird of the week was a Firecrest, with a supporting cast of Redstarts and Spotted Flycatchers. A Teal was caught in a hand-net on North Pond after midnight, after one of many evenings ringing Manx Shearwater juveniles along the track from the Cottage to the Lighthouse.

Our total of new birds ringed was 508, including 187 Manxies and 141 Chiffchaffs, with 130 retraps.

Hwyl fawr, a diolch.

Thursday, 18 September 2014

Juvenile dispersion of Cetti's

News from the BTO of the ringing details for this Cetti's Warbler that we caught on the Teifi Marsh last April.
It was ringed as a juvenile at Llangorse Lake near Brecon last August, 2013

This is the second control Cetti's that we have caught on the Teifi - the last was ringed on Farlington Marsh, Portsmouth.
The four new Cetti's ringed on the reserve last week might also not have been bred here but dispersed from other sites.
The BTO Migration Atlas helps us understand the movements of birds like this, a useful addition to any ringers book collection.
From the chapter on Cetti's Warblers - it is thought that they move very little once established as breeders but juveniles may move in their first autumn continuing into April before they settle. Females seem to be more mobile than males. These juvenile dispersive movements are relatively extensive compare with other sedentary species, probably because of the scarce and dispersed nature of the Cetti's Warblers habitat.