“Increasing the Biodiversity of the Pine Forest” is a project carried out by the Zamalla Ornithological Group, To improve the biodiversity of the Gilena public pine forest in Seville. We would like to thank you for your work and commitment over the years to improving the environmental conditions of the natural surroundings and, as in this project, providing development opportunities for a wide variety of bird species.
Furthermore, for Explore Nature It's an honor to be able to publish the development of this project, something we will do in different blog posts.
This text has been written by Francisco Javier Pérez, president of Grupo Ornitológico Zamalla and member of Explora Natura.
«"Increasing the biodiversity of the pine forest"»
“Increasing the Biodiversity of a Pine Forest” is the motto chosen for a project based on the placement and monitoring of nest boxes for birds in the public pine forest of Gilena in the province of Seville. This reforested pine forest serves an important protective function and now attracts many nature and sports enthusiasts seeking to immerse themselves in a forest far from the noise and stress of daily life, yet just a few kilometers from their towns. The only drawback of these single-species forests is the limited biodiversity they support.
For this reason, the Zamalla Ornithological Group began this fascinating project back in 2004, aiming to increase the number of cave-dwelling species. We're not talking about prehistoric animals, but rather all the small birds that need natural cavities to build their nests, such as great tits and blue tits. Since they rarely find suitable nesting sites in young pine forests, we selected a specific area for this project to install these artificial nest boxes—no fewer than 92 as of 2018.
What results have we obtained?
Over the years, we have observed an increase in forest bird populations. To illustrate, consider this: in 2004, only two species nested in our nest boxes, occupying 151 boxes; but by 2018, a total of seven species were breeding, occupying 551 boxes.
Many species breed or have bred here: Great tit, coal tit, blue tit, crested tit, wren, spotless starling, hoopoe or European treecreeper.
Each species has a different requirement; it is no coincidence that their numbers are increasing, since the renewal and replacement of nest box models is an important part of the project, and with this we achieve greater diversity.
How do we monitor the project while increasing the biodiversity of the pine forest?
The chosen design is generally classic, with boards made of varying materials: wood or plywood. The most important factor is the safety of the brood being raised; for this reason, the boxes have been securely assembled and built to withstand harsh weather conditions. For example, the nails used have been installed perpendicular to the force of gravity. The roofs are sloped and protrude from the body of the box to prevent water damage. In most boxes, the roof is used to open the box for inspection, with small holes in the bottom for ventilation and drainage. Subsequent restorations have incorporated improvements and new designs.
Installation and monitoring are carried out using extendable aluminum ladders, as the boxes are placed between 3.5 and 5 meters high. They are anchored to the trunks with a quick and easy removal and replacement system to make working at height as comfortable as possible and avoid damage to the tree. Another placement system tested in the project involves attaching the boxes to branches with a hanger, suspending them from the branches.
As you can see, this is a job that requires consistency and effort. In spring, we monitor the nests and the species that occupy the boxes. And in autumn, we use the time to repair damaged boxes, add improvements, or plan new projects—in short, to devise new ways to keep ourselves busy on weekends.
Milestones and curiosities
The project's timeline includes important milestones that have solidified its place within the ecosystem and among the people who frequent the pine forest. It is, without a doubt, one of the flagship projects of the Zamalla Ornithological Group.
In 2004 The project begins with 100 small artificial nest boxes with entrance hole for tits.
The first three years were decisive in serving as experience. The anchoring to the tree was improved; there was a lot of damage caused by dormice, so several boxes were protected. At that time, 37 boxes were lost and not replaced.
Up to 63 nest boxes were left for the 2008 breeding season. In 2009, 2010, and 2011, no visits were made to the project area; we only collected the broken boxes that were given to us, which is normal given the time they spend exposed to the natural environment.
In it In 2012, the monitoring restarted. The exhaustive inspection of nest boxes was a success this year, as the breeding of all six cave-dwelling species was confirmed, which in order of abundance are: Great Tit, Eurasian Treecreeper, Coal Tit, Blue Tit, Wren and Crested Tit.
During the maintenance of nest boxes after the breeding season In 2013 we placed a front plate on the opening to prevent rodents or woodpeckers and the damage they could cause. This was crucial, since We lost the European treecreeper as a breeding animal, We noticed that this species climbs up the box and inside, something impossible with the front panel. We solved this problem with a mixture of sawdust and glue, which improves the bird's grip and Since 2015 it has been a common species in the project.
But unfortunately, since 2015, which was their last breeding attempt, There is no trace of the crested tit. This same year we designed and installed a large nest box for a tawny owl, a common inhabitant in this pine forest.
The last few years
The year 2016 served as a pilot experience for another new design of nest boxes, Designed for the treecreeper, this will be a mailbox-type box with the hole on the side.
In 2017 we introduced 2 large nest boxes made of natural cork for hoopoe, green woodpecker or little owl.
2018 has also been a season full of new developments. We replaced 10 tit nest boxes but a little large in size compared to many smaller ones, and the entrance hole is smaller. This has encouraged the breeding of common blue tits and coal tits, two smaller species and that the common tit (larger and more aggressive) kept in check in their territories.
Another design is introduced into the pine forest, this time 3 boxes with open fronts, to encourage the breeding of the spotted flycatcher, robin…We also repaired an excessively large tit nest box and converted it, by widening the opening, into a hoopoe nest box. Interestingly, this year a great tit nested successfully in one of these open-fronted boxes.
Evolution of the increase in biodiversity of the pine forest
During these years a decrease in the pine processionary caterpillar. Years ago, it was a common sight to see nests of larvae on pine trees, a very dangerous sight for people as it causes hives and skin problems. It is also extremely dangerous for domestic dogs, even causing death. Today, this area is free of the infestation; only a minimal ecological population remains, something the ecosystem can easily manage.
The results show a significant increase in the biodiversity of the pine forest. In upcoming posts, we'll reveal the steps and evolution of the "Increasing Pine Forest Biodiversity" project. You'll see how the results evolve over the years. Stay tuned to the Explora Natura blog.
