Birds in agroecological systems

Birds in agroecological systems: indicators of change and allies of biodiversity

Birds as a Mirror of Land Health –
In ecology, it is well known that the composition of animal communities reflects the state and quality of ecosystems. Among these, avifauna occupies a privileged place: the great variety of species, ease of observation, and their presence in nearly all environments make birds excellent ecological indicators.
With approximately ten thousand species distributed worldwide—many of them migratory—birds offer valuable information on the state of land health. From landscape planning to environmental impact assessment, their observation provides useful data for understanding environmental changes and guiding more effective protection policies.

Decline of Agricultural Birds –
In recent decades, however, there has been a sharp decline in bird populations associated with agricultural land. According to European estimates, populations of farmland birds and meadow butterflies have declined by more than 30% since 1990. The main causes? Agricultural intensification, habitat loss, and the widespread use of pesticides.
The European Court of Auditors also recommended that the EU Commission improve the monitoring of biodiversity spending, strengthen the contribution of the Common Agricultural Policy (CAP), and develop more reliable indicators to measure the impact of agriculture on ecosystems.

The ecological role of birds in agriculture –
Protecting avifauna is not only a matter of conservation, but also of ecological balance.
Birds actively participate in the functioning of agricultural ecosystems: they spread seeds, promote pollination, control pest populations, and contribute to nutrient recycling through their droppings.
Species such as great tits, robins, tits, and woodpeckers feed on insects that damage crops, reducing the need for insecticides. Others, such as gulls and hawks, contribute to the nutrient cycle by transporting useful organic matter to the soil.
Unfortunately, insectivorous species in agricultural areas—such as skylarks, shrikes, tree pipits, and whinchats—are rapidly declining. Conversely, species less dependent on insects (such as storks, kestrels, or yellowhammer) show a more stable trend, while some forest insectivores (such as swifts or bee-eaters) are actually increasing.

The domino effect of insect disappearance –
This decline is caused by another ecological crisis: the drastic decline of insects.
In Central Europe, long-term studies have highlighted a 75% reduction in insect biomass in less than thirty years. The loss of favorable habitats, the use of pesticides, and intensive grassland management are among the main causes.
Meadows mowed up to six times a year, the use of machinery that destroys insects during mowing, and herbicides that eliminate nectar-producing plants have reduced the availability of food for insectivorous birds. Antiparasitic treatments for livestock, by limiting insects in manure, also exacerbate the situation.

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The Impact of Plant Protection Products –
Insecticides, in addition to targeting pests, harm many non-target species, profoundly altering the food chain.
Historical examples such as DDT, banned in the 1970s, show how persistent and fat-soluble substances can accumulate along trophic levels, causing the decline of birds of prey. Even neonicotinoids, initially considered less dangerous, have proven harmful to bees and other pollinators, prompting the European Union to severely restrict their use with Regulation (EU) No. 485/2013.
However, in some European countries and Switzerland, these pesticides continue to be used under exemptions or at home, contaminating waterways and areas designated for biodiversity. Studies conducted in the Netherlands show a direct correlation between neonicotinoid concentrations and the decline in insectivorous birds.

Modern Agriculture and Habitat Loss –
Contemporary agricultural techniques—high levels of fertilization, more productive varieties, and dense crops—make meadows and cereal fields denser, limiting birds’ access to their prey.
Species such as the common redstart, the wryneck, and the hoopoe prefer environments with sparse vegetation, where hunting is easier: their disappearance signals an increasingly uniform landscape lacking in biodiversity.

Towards a more ecological agriculture –
Reversing this trend is possible. The principles of agroecology offer concrete solutions to restore the balance between productivity and wildlife protection. Among the most effective measures:
1. Leave at least 10% of meadows intact after each mowing, providing shelter and breeding grounds for insects.
2. Severely limit the use of pesticides, using them only above actual damage thresholds. Studies show that a 40% reduction does not lead to significant yield losses.
3. Promote consumer awareness by encouraging the purchase of products grown with fewer pesticides.
4. Manage green areas in specialized crops, which are often over-tended, more naturally.
5. Involve gardeners and citizens in creating insect-friendly green spaces.

Conclusions: A systemic approach –
The decline of agricultural birds is a wake-up call for the need to rethink the entire agricultural system from an ecological perspective.
The European Farm to Fork and Biodiversity 2030 strategies have charted the course, but regulatory and practical tools for a real transition are still lacking. Policies are needed that integrate agriculture, natural habitats, and society, recognizing birds—and fauna more generally—as sentinels and guardians of ecosystem health.

Guido Bissanti