These 324 migrating birds have spent their winter in Tagus Estuary

The vegetation along the salt marshes in Quinta da Atalaia in the Tagus Estuary, one of the most important European wetlands, was the chosen spot for these 324 birds to spend their winter. How do we know? Tagus Estuary Ringing Group was there and told us.

Kingfishers, robins, common chiffchaffs, nightingales, great tits and many other small birds are part of the winter landscape of this quiet spot in Tagus Estuary. To better know the species spending there the coldest months of the year, a team of ornithologists installed nets and set up ringing tables in eight sessions, 15 days apart, from 15^th November, 2015 to 15^th February, 2016.

These counts are part of the Wintering Birds Monitoring Project (MAI, in Portuguese), taking place since 2011 in several parts of the country, from the Central and South coast to the interior Alentejo. This is the first year that ringings are made in Quinta da Atalaia (Alcochete), explained Afonso Rocha, one of the project organizers.

When the ringing sessions were finished – in which an average of seven people participated -, the birds were counted. According to the recently known results of 2015/2016, 324 birds were captured, 277 of which were marked with metal rings of the National Ringing Center.

The most surprising thing was the 221 common chiffchaffs captured. This “is a very high number and exceeded our expectations”, Afonso Rocha said. The old salt marshes habitat, with surfaces of little dynamic water, surrounded by vegetation is very rich in insects, which attracts these small birds. This is the main reason for the capture of a large number of that species compared to others.

Besides common chiffchaffs, the ornithologists – from professionals to volunteers – captured 32 Cetti’s warblers, 19 blue tits, 10 bluethroats, among many other birds.

This program of regular bird ringing during winter and in specific habitats is important to help “understand the geographic origin of populations of wintering birds, evaluate interactions between wintering and resident populations and study fidelity to winter territories”, Afonso Rocha added.

And Portugal is not alone. MAI is part of the European Project EURO-CES Constant Effort Ringing in Europe, an initiative that began in 1981 by a volunteer. In 1986, the project grew to a national scale and since then it has spread to several European countries. The idea is very simple. Birds are an indicator of environmental changes and of the use of soil. To understand these changes it is necessary to know what is happening to birds. “Ringing, methodically and steadily done, can be very useful to know the demography of populations, such as mortality and birth rates, for example”, the EURO-CES website explains.

According to Afonso Rocha – member of the team that developed and implemented the Project in Portugal-, “most abundant species of birds in wintering period and commonly captured during the ringing sessions, such as european robin, common chiffchaff, Eurasian blackcap, Cetti’s warbler and commom reed bunting are considered a priority”.

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Here is the list of wintering birds monitored in Quinta da Atalaia:

Alcedo atthis – 3

Carduelis spinus – 2

Cettia cetti – 32

Cisticola juncidis – 1

Emberiza schoeniclus – 2

Erithacus rubecula – 4

Estrilda astrild – 9

Luscinia svecica – 10

Luscinia svecica cyanecula – 4

Parus caeruleus – 19

Parus major – 1

Passer domesticus – 2

Phyloscopus collybita – 221

Rallus aquaticus – 1

Saxicola torquata – 1

Sylvia atricapilla – 2

Sylvia melanocephala – 3

Turdus merula – 6

Turdus philomelus – 1