Áudio

Pygmy bird

On 23 of May, in Pangrango NP, me and Santi came across with a Pygmy Tit’s nest ,Java’s smallest bird. With a length of 8 cm’s it surely deserves this distinction and name.

The Pygmy Tit (Psaltria exilis) is placed in the Aegithalidae family but his true relationships remain obscure. The genus Psaltria is endemic to Java and Bali.

Little is known about its breeding biology, and even nowadays the juvenile plumage remains undescribed, although is believed to be very similar to the adult plumage.

Around 1h15 pm we noticed activity around the nest and we took the opportunity to take some notes.

Arrow shows the nest entrance place.
Arrow shows the nest entrance place.

The nest is in a Rasamala tree, around 10 m from the ground. We could see it up close from a Canopy trail.

The nest structure is no more than moss coupled to an epiphyte. The bird took advantage of this structure to build the nest or could it be used as camouflage?

Sketch of the nest structure.
Sketch of the nest structure.
Sketch of the nest structure - detail.
Sketch of the nest structure – detail.

We noticed the birds joining mixed flocks to collect food and returning to the nest each time the flock passed at the area. Seicercus grammiceps and Phylloscopus trivirgatus were the main species on those flocks.

The only prey we saw being taken was small caterpillars.

In one occasion we saw 3 birds around the nest, bringing food. One of them entered into the nest and remained there, while the others were foraging. This strongly suggests cooperative breeding.

The time length between each visit was very long, 18 to 40 min.

We didn’t manage to get views of the nestlings, but they seemed very young, assuming from the noise coming from the nest.

http://www.xeno-canto.org/246131/embed?simple=1

The surrounding area is Primary forest (transitional from sub-montane to montane vegetation), composed mainly by tall Rasamala trees. The nest tree is located in a valley (around 1500 m elevation), with a fast flowing stream passing by.

Anúncios

Arctic warbler split

As a Portuguese birdwatcher, Arctic warbler has been, for a long time, a most wanted bird and one of the rarities that one wishes to tick.
So far there’s only one accepted record in Portugal. In 2009 (September 28) a juvenile was ringed in Santo André lagoon  by Carlos Pacheco and others (see here).

This species winters primarily in Malaysia, Phillipines and Indonesia.

I’m currently in Java, and the opportunity to observe and study Arctic Warblers in the wintering grounds seems irresistible.

But here arises a problem…

Arctic Warbler has now been split into three cryptic species due to differences in genetics.

Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”
Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”

The split was proposed in 2011 in the following paper: “Alström, P., Saitoh, T., Williams, D., Nishiumi, I., Shigeta, Y., Ueda, K., Irestedt, M., Björklund, M., and Olson, U. (2011). The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed. Ibis 1532: 395–410”, an abstract of which can be seen here and here.

According to this paper distinguish these three species will be impossible by plumage alone, leaving us with calls and songs as the only safe method of ID.
On February 7, 2015 in Bogor Botanical Garden  a warbler caught the attention.

Plumage and structure seemed to be typical of Arctic warbler, although much greyish in tone than a previous bird seen at the same place, identified as Phylloscopus borealis (photo here). But as we already know plumage is of little use in the field.

Fortunately it was calling and I managed to get this recording:

http://www.xeno-canto.org/212895/embed?simple=1

The double note call seems to indicate Phylloscopus examinandus. Looking at the sonogram we can see two syllables:

Sonograma examinandus

If we compare to the example in the previous paper we can see similarities:

Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”
Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”

On March 18, 2015 an Arctic warbler Phylloscopus borealis was recorded at the same place. It was much silent than the previous bird. Only calling randomly, a single note call:

http://www.xeno-canto.org/229193/embed?simple=1

The sonogram shows one sillable:

Sonograma borealis18_3

Comparing with the sonogram in the paper we can see the same pattern:

Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”
Extracted from the paper “The Arctic Warbler Phylloscopus borealis– three anciently separated cryptic species revealed”

Today I managed to record another Arctic warbler P. borealis, a single note call given when I approached the bird:

http://www.xeno-canto.org/233578/embed?simple=1

The sonogram:

Sonograma borealis30_3

I would like to hear some inputs on these observations, especially on the recording of P. examinandus.