Birds – Farmers’ Best Partner

They collect seeds from the field, pick berries off trees, and harbor pathogens. Birds are often depicted as a farmer’s worst enemy. However, a large number of bird species can be quite beneficial in the field, if given the chance to shine. How can birds be your growing ally?

When the insects breed in the spring season, birds feed them to their chicks while plants are small and vulnerable to emerging pests. In fact, birds can have pest control benefits, which far outweigh those of conventional chemical sprays. According to CASILLAS, 2021, species like sparrows, can collect over 135 insects to feed their young in a single day, while barn owls can consume over 1,300 field mice, voles and shrews in one year.

As confirmed by the Wild Farm Alliance, an increased diversity of birds on land can reduce pest problems and improve yields. Sometimes the effect of birds goes beyond what they eat. While raptors certainly prey upon rodents or pest birds in agricultural fields, the raptors’ mere presence can also create a fear response in their prey, which can reduce crop damage.

But birds that consume fruit or nuts in season can later become beneficial to the farm again. In nut crops, for example, birds clean up the leftover “mummy” nuts that would otherwise harbor overwintering pests.

Here are three concrete examples extracted from Wild Farm Alliance’s “Supporting Beneficial Birds and Managing Pest Birds” and based on several types of research which highlight the role of beneficial birds in agriculture:

Tree- and Ground-Foraging Birds Lessen Pest Insects in Olives

Birds help reduce Olive Fruit Flies in two stages: larvae in the fruit and pupae on the ground. The olive fruit that was eaten by the birds mostly contained larvae (Bigler et al., 1986) suggesting that birds do not have a negative impact on production. In this context, birds consumed 65–71% of the pupae in soil, and ants attacked most of the rest (Pienkowski and Beaufoy, 2000)

Habitat and Co-Existence in Corn Result in Pest Control

Birds reduced corn insect pests by 34–98% in various studies. Significant reductions in some cases were tied to nearby habitat patches that provided shelter for birds. Some of the beneficial birds later on became pests.

Hedgerows in Kale Increase Pest Control

More Cabbage Looper caterpillars were consumed by birds near shrubby field margins than near other uncultivated areas. On average, caterpillars to which birds had access were reduced by 24% (Garfinkel and Johnson, 2015). Yet, results suggested when the pests numbers were low, birds were not as effective.

In two separate kale studies, birds were beneficial in reducing caterpillars near shade trees; did not reduce aphids’ natural enemies (Guenat, 2014) and reduced aphids and their leaf damage three times more than when birds were excluded (Ndang’ang’a et al. 2013).

Birds are excellent indicators of ecosystem conditions because they are responsive to environmental change, have important ecological functions – such as seed dispersal and insect consumption, and are easy to observe. In healthy landscapes, seed eater, foliage grazer, insectivore, nectivore, omnivore, and carnivore birds can represent the full range of trophic levels. Changes in land use and management affect shelter, food, and habitat resources available to birds. Collectively, these characteristics make birds an excellent practical indicator to monitor and report the health of biodiversity on the property.

Researchers found that fields with surrounding natural habitat experience less crop damage and lower food-safety risks, highlighting that birds do more good than harm on farmlands.

A study conducted by the University of California Davis found that keeping natural habitats surrounding farmland intact can reduce the spread of pathogens and damage from wild birds to crops.

The experiment, surveyed 21 strawberry fields and showed that wild birds were more likely to feed on berries and spread pathogens in the fields that were not surrounded by natural habitat. The fields with surrounding natural habitats saw less crop damage as a result of wildlife than those without.

The pressure on farmers to remove natural habitat around maintained and farmed land came after an E. coli outbreak as it was believed that removing the surrounding habitat would keep wildlife, and any pathogens they carry, away from farmed land and crops.

For the study, scientists looked at the molecular analysis of 1,000 fecal samples from 55 bird species, combined with data from more than 300 bird surveys. They used the information to figure out what each bird was eating—be it pests, beneficial insects or crops—as well as which birds were carrying pathogens. Using this data, the scientists then ranked which birds were most detrimental to farmland and which were the most beneficial.

Scientists found that the single most important factor in whether birds of any species were doing more harm than good—or vice versa—to farmed land and crops was how the surrounding land was managed. And farms with surrounding natural habitats for birds constantly saw less damage and fewer pathogen problems than others.

According to this publication, a related study in 2020 found that “farms with natural habitat attracted more insect-eating birds and fewer strawberry-eating birds so that farmers experience less berry damage on farms with more habitat nearby.”

Karp said in the study, “All together, these studies suggest that farming landscapes with natural habitat tend to be good for conservation, farmers and public health.”

by Eng. Maryse Bou Zeid