While the reproduction of waterfowl usually starts in April, with the first liaisons and nest building, the month of June is the peak of the birds’ life cycle. Around these days, red-crested porchards, Northern pintails, Eurasian coots, purple gallinule, grebes and other waterfowl can easily be observed accompanied by their offspring.
This is the period when the birds make a greater selection of their habitat. Not surprisingly, the survival of the species (or at least what the genes “say” to each of them) requires finding the best place to make a nest, ensuring plenty of food and shelter from predators whom in return need to prey on other birds to be able to feed their own offspring.
For their different configurations, constructed wetlands offer slightly different habitats for waterfowl in relation to the level of flooding, the vegetation structure and floristic composition of their plots. It is thus by studying the variation of microhabitats that we obtain precise information on the habitat requirements. We are currently beginning to understand some of the processes in each of the sites:
- The Tancat de la Pipa, with more open lagoons and a filter system with sparse vegetation, offers suitable environments to a wider variety of waterfowl species, but in small numbers.
- The Tancat de Milia, with greater coverage of bulrushes on flooded soil, but with low density offers suitable environments for the reproduction of two of the most interesting speciesfor the project:the cootandlittle bitterns.
- The Tancat de l’Illa, with a very high density of eneas, together with an abundance of small and medium-sized fish, is a highly appropriate place for breeding heron and bittern.
But the importance of monitoring the reproduction process is not only about knowing the reproductive habits of the species. There is much more information to be measured that defines the suitability of nesting habitat or feeding birds: productivity, for example. To realise the monitoring of family groups and learn more about the habitat they use and the survival of their offspring gives us the ideal opportunity to assess whether a habitat is suitable or just seems to be suitable. A place where four birds are born and out of those three reach adult size is more adequate than a place where 12 birds are born and none of them reaches adult size.
Using the information from this project, we will promote the management which favours the former.