6 Sep 2024

Country Life: Why farmers need birds

4:50 pm on 6 September 2024
Dr Sara Kross

Dr Sara Kross Photo: Hayden Oliver

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How do you stop birds colliding with New York's skyscrapers and how can New Zealand farmers benefit from bird-friendly planting?

These are just some of the questions Sara Kross has been trying to answer from her research lab at Canterbury University.

A senior lecturer in terrestrial ecology, she grew up in New York "right in the thick of the city", but was attracted back to New Zealand, where she did her PhD on the kārearea in Marlborough vineyards, because she'd noticed something "exciting" happening.

"Coming back to visit family and collaborators here in New Zealand, I started noticing just how many hedgerows were being planted by farmers here, they are popping up everywhere," she said.

"It's really, really exciting, because this is, I think, a truly grassroots effort by farmers to increase the biodiversity value of their properties while continuing to do really productive farming in those landscapes."

Shelterbelts on the Canterbury Plains

Shelterbelts on the Canterbury Plains Photo: Sara Kross

Studies in Europe and California show hedgerows - or shelter belts and other non-crop small-scale planting often in straight lines - can play an "enormous" role in sustaining a large diversity of species, she told Country Life.

"Increasingly, we're finding less common species and rare species using those habitats, either to make their way from one conservation area to another, or as stopovers during migrations and we're only just, I think, scratching the surface of the role that these habitats can play."

Her research team is trying to find out the "net effect" of having birds on farm as many birds provide services and economic benefits to farmers such as eating pest insects and acting as pollinators in the springtime.

There is much to disentangle in the New Zealand context, she said, as large shelter belts may be maintaining large populations of introduced birds that are often the main pests of crops.

"Whereas the native hedgerows are more likely to provide habitat for our native species, many of which are actually insectivores or insect-eating species year round."

A native hedgerow and exotic shelterbelt planted alongside a Canterbury road

A native hedgerow and exotic shelterbelt planted alongside a Canterbury road Photo: Hayden Oliver

The use of birds as a friend and not a foe in farming systems is not a new field. Before the pesticide era they were a common tool in the quest to grow food.

In the early 1900s there were whole offices under the US Department of Agriculture that were focused on a field called economic ornithology, Kross said.

Her research team is starting to map hedgerows on the Canterbury Plains so they can better understand their effects on birds and farming systems.

Some of Sara Kross' collection of publications from the early 20th century on the benefits of birds on farms

Some of Sara Kross' collection of publications from the early 20th century on the benefits of birds on farms Photo: Sara Kross

Bird collisions

Kross also studies human and wildlife interactions in towns and cities.

Recently published research out of the Kross Conservation Lab has focused on how to save birds in New York.

Thousands of birds die in the city each year as they collide with glass-encased skyscrapers, which happen to be along the Atlantic flyway, a major migratory path for birds.

Kross said the research results were helping to inform when buildings should try to turn their lights off. Buildings lit up at night are confusing for the birds and are a major contributor to collisions.

"Understanding the wind conditions and the weather conditions that also lead to higher rates of collisions means that we can fine-tune predictions a bit better, so that we can really work with building operators to try to reduce that light pollution on the most dangerous nights for birds."

With the resurgence of native birds in New Zealand's cities this will become more of an issue in Aotearoa, she suspects.

Learn more:

  • Learn more about Dr Sara Kross' research here
  • Find out more about recent research into bird collisions in New York Ciry

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