A late start

Post date: Sep 8, 2014 5:38:11 PM

This year, after maintaining a constant-effort site in Sweden (see Krankesjöns Ringing Station), I started ringing in Portugal quite late in the migration period. The objective is to determine the relative importance of various Portuguese wetlands for the migration of Aquatic Warblers (Acrocephalus paludicola), using a standardised method that should be carried out during the peak of occurrence of this species (end of August and beginning of September). Various collaborators are help me out to achieve this. Other objectives include collecting blood samples for a malaria study and colour-ringing the local Reed Buntings (Emberiza schoeniclus lusitanica), collecting further information for my ecological speciation study.

On the 5th September, I visited Salreu marshlands, where I have been working since 1997. My regular ringing sites for Aquatic Warblers were dry, with part of the vegetation cut. So, I prepared a new ringing site on the edge of a rice field, close to where I first photograph them in Portugal (one of the photos here) and had a few observations in previous years. The rice fields are extensive, have plenty of other vegetation and large insects as well as, importantly, an adequate water level, constituting a very good habitat for Aquatic Warblers. While I was preparing the line, I set up a few "single" nets quite late in the morning that captured only one bird, but it was a Sedge Warbler (Acrocephalus schoenobaenus) with a British ring! That was a good start of the autumn campaign!

Today, I undertook the first ringing session using three 15 m nets by the rice field, song playback, and an extra 15 m net on the edge of a cornfield. I had the company and help of Tim van Nus, a new trainee from the Netherlands who spends some time in Portugal every year. Unfortunately, we did not trap any Aquatic Warbler, but the session was quite nice, with plenty of birds despite the few nets. Results were as following (retraps between parenthesis):

Acrocephalus schoenobaenus 12(1)

Acrocephalus scirpaceus 15(1)

Anthus trivialis 7

Carduelis chloris 1

Cettia cetti 4

Estrilda astrild 2

Euplectes afer 14(3)

Locustella luscinioides 1

Locustella naevia 1

Luscinia svecica 3

Passer montanus 2

Phylloscopus trochilus 1

Saxicola torquatus 1

The exotic birds, especially the Yellow-crowned Bishop (Euplectes afer) are becoming extremely common, especially around the rice fields. During the last few years they became the third commonest species in the area, as measured by regular mist-netting.

Two of the birds caught today: Tree Pipit (Anthus trivialis) above, and Stonechat (Saxicola turquatus/rubicola)

So far this year, only two Aquatic Warblers were trapped in Portugal: one at Salreu and another at Lagoa de Santo André, but hopefully there will be more soon. As usual, my ringing totals of the year in Portugal (which this year are mostly those captured during summer/autumn) are described in the ringing sub-webpage.

More news soon!

Júlio M. Neto