Spring breeding - Nest box project

If you take a stroll along the wooden boardwalk thats run through the marshes of Urdaibai bnear Kortezubi and Arteaga you will probably spot a number of wooden nest boxes up in the trees. If you are lucky you might even catch sight of a blue tit or great tit entering the box with a beakful of insects. These busy birds are taking food to their young that are warm and sheltered inside the nest boxes. The boxes and their occupants are part of an interesting study being carried out at the Urdaibai Bird Center. A month ago 55 boxes were placed in trees in 2 different habitats in Urdaibai. Half were placed in open fields and the other half in marshlands.

Over the last few weeks we have been monitoring the progress of the boxes every week. Almost all of them are occupied by blue tits and great tits. We have been able to document the fascinating process of nest building, laying, incubating and hatching during our study. 

There is an interesting case of one female with at least 11 eggs and we believe that such a large number of eggs would actually have been laid by 2 females.

The aim of the study is to monitor the breeding success rates in the two different habitats and to see how factors such as the weather affect the birds and their broods.

Why dont you take a walk through the Urdaibai marshes and see if you can catch a glimpse of these wonderful little birds and their families.

Soon the chicks will be fledging so you might even witness a first flight!