Pesticides and Intensive Agriculture Clearing Displace Essential Birds for Pest Control

Intensive agriculture involves the use of fertilizers and pesticides, a practice contributing to the decline of insectivorous birds, which are beneficial for pest control. A study led by UMH highlights the risks posed by this type of agriculture, both in terms of pollution and biodiversity loss. Therefore, the authors advocate for the use of ecological pest control methods, such as those provided by insectivorous birds, many of which are displaced in search of food due to the massive use of pesticides and clearing practices.

The research was conducted over four years, analyzing the reproduction of an insectivorous bird, the red-necked nightjar (Caprimulgus ruficollis), on two citrus farms in central Murcia. Despite being adjacent, one farm is managed intensively with pesticide application and significant clearing, while the other is operated under organic production.

Contrary to expectations, UMH explains, nightjars from both farms show similar reproductive success. However, unlike those from the organic farm, nightjars from the intensive farm are forced to travel far from their nests to obtain the food needed for successful reproduction.

The study authors explain that, over recent decades, intensive agriculture has expanded worldwide in response to the growing demand for food driven by human population growth. Unlike organic farming, intensive agricultural practices involve the massive application of fertilizers and pesticides, contributing to the widespread decline of birds associated with agricultural environments, particularly insectivorous species.

In contrast, organic agriculture is based on the application of biological control methods to combat pests, thereby minimizing environmental pollution and avoiding negative effects on biodiversity.

"The extraordinary abilities of nightjars to camouflage their nests have challenged the study of their reproductive biology, resulting in very few studies with a sufficient number of nests to draw robust conclusions," says José Manuel Zamora Marín, researcher at the Agro-food Research and Innovation Centre (CIAGRO-UMH) and lead author of the study.

Nightjars from both farms had similar reproductive success despite the presumed lack of insects on the pesticide-treated farm. The next step in the research was to determine how the birds could compensate for this limitation. GPS tracking revealed that nightjars breeding on the intensive farm frequently traveled to adjacent feeding areas far from the nests (2-8 km), compared to those from the organic farm, which fed within the farm itself.

The authors emphasize the need to promote the presence of unique landscape elements, such as hedges, small water bodies, fallows, and patches of natural habitat, which can offer alternative feeding areas for birds and increase connectivity between breeding and feeding areas. "Implementing these measures in agricultural spaces would maintain good populations of insectivorous birds, which in turn can act as natural controllers of agricultural pests," adds UMH expert Zamora Marín.