Why Organic is Better for the Birds and the Bats

Enhancing plant growth, removing pests and getting rid of weeds; these are all important for achieving successful crop yields on farms and can be achieved using a variety of different methods and substances, both natural and artificial. But at what cost to wildlife?

Organic goods are generally those that have not been sprayed with artificial fertilisers or pesticides during farming, and the soil has to have been maintained this way for 2 years before being certified as organic (gov.uk website, 2016). They are instead treated with natural fertilisers like manure, use biological pest removal (introducing or encouraging living predators that will eat the pests), are hand-weeded and grown using more environmentally friendly practices.

Non-organic products on the other hand (probably most of the food items found in our local supermarkets) have been sprayed with chemical fertilisers and pesticides. Whilst these synthetic versions are cheap and fast-acting, they are far less eco-friendly than organic practices and have fatal consequences for wildlife, particularly for our lovely birds and bats…

Agricultural Field.

Pesticides are not indiscriminate! Not only do they exterminate pests, but they also get rid of a whole array of other innocent bystander insects – including those that make up the diet of birds and bats! When these insects are killed off, there are very few left to feed birds and bats and so many of these animals are left to starve. Similarly, pesticides can also alter the plants and habitats that are available, and consequently which insects are available to predators. This has indirectly, but greatly, contributed to population declines of many UK birds and bats over time.

It is particularly harsh on the young, who fail to make it to adulthood because they can’t get enough food to survive. Research by the Game Conservatory Trust in Sussex named pesticides as a major indirect cause of the decline in grey partridges. Specifically, broad spectrum insecticides and herbicides were shown to indirectly reduce chick survival by decreasing food availability.

Grey Partridge Photo © David Galavan (see end).

A well-known example that illustrates the negative effects of certain pesticides on wildlife is the widespread use of DDT and other organochlorine pesticides across the UK during the 1950’s and 60’s. When pesticide-contaminated prey items were eaten by predators, they became contaminated themselves and, as such, the pesticide quickly accumulated up the food chain. What’s more is that the pesticide became far more concentrated (and deadly) as it moved up the food chain, meaning that even if a plant or insect had a small concentration of pesticide in its body, by the time it reached top predators such as birds of prey the concentration was so high that it caused thinning of birds’ eggshells (which then cannot support the chicks inside) and increased death rates.

Poor Peregrine Falcons! They were hit particularly hard, and 80% of the UK population was wiped out by the early 1960’s. When DDT was banned in the UK in the early 1980’s, Peregrine Falcon numbers returned back to normal by the late 1990’s. Whilst this is an extreme example, and DDT is now banned here, it does demonstrate how artificial pesticides used in non-organic farming can have huge negative impacts on wildlife.

Peregrine Falcon – Bird of Prey.

Are pesticides to blame for the decline of bats? Bat numbers have been decreasing for many decades in the UK, and the overuse of pesticides is one of the possible reasons why. One study of UK bat prey items found that insect abundance was significantly higher on organic farms than in the same habitat-types on non-organic farms. With fewer insects to eat in chemical-sprayed fields, many bats are either having to find new places to forage or risk starving.

Pipistrelle bats © Steve Wadley.

Organic farms seem to be a haven for many bird and bat species during this age of high chemical fertiliser and pesticide use. Whilst they have their benefits, artificial fertilisers and chemicals can have devastating effects on wildlife. Not to mention the detrimental impacts these harsh chemicals have on soil quality, too! Organic products may be a little more expensive, but even switching just a few items from your weekly shop to the organic versions could benefit your local wildlife. Give it a try!

Image attribution:

Grey Partridge Photo © david galavan - grey partridge at turvey, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=21237601

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