Your data on MRCVSonline
The nature of the services provided by Vision Media means that we might obtain certain information about you.
Please read our Data Protection and Privacy Policy for details.

In addition, (with your consent) some parts of our website may store a 'cookie' in your browser for the purposes of
functionality or performance monitoring.
Click here to manage your settings.
If you would like to forward this story on to a friend, simply fill in the form below and click send.

Your friend's email:
Your email:
Your name:
 
 
Send Cancel

Urban light pollution linked to smaller eyes in birds
The northern cardinal's eyes were five per cent smaller if they lived in the city.
Birds living in cities had smaller eyes than those on outskirts.

A study has suggested that the lights in cities may have resulted in some birds evolving to have smaller eyes.

The researchers, from Washington State University, discovered that some birds living year round in the urban setting of San Antonio, Texas, had eyes that were smaller than those in the less bright outskirts.

The investigation involved them studying more than 500 birds from central and edge areas of San Antonio, a major city in Texas. The researchers compared the body and eye sizes of the birds, and analysed noise and light measurements during night and day in each area.

Two songbird species, the northern cardinal and the Carolina wren, had eyes that were five per cent smaller if they lived year-round in the city, compared to members of the same species in the outskirts.

However they found no eye-size difference between the two species of migratory bird, the painting bunting and the white-eyed vireo, no matter where in the city they predominantly lived.

This may suggest that residential birds are adapting to the brighter lights of urban areas, while the time migratory birds stay away from these places means that they have not. This could make it challenging when they return to these areas to breed.

Developing smaller eyes over time may be helping the birds to deal with the brighter, constant light of city environments, whereas birds with larger eyes could be somewhat blinded or struggle to sleep.

This is the first known study to show a connection between eye size and a bird’s ability to cope with sensory pollutants as part of city life.

Todd Jones, the study’s first author, said: “Humans may have some unintended consequences on birds that we don’t realise,

“We don’t know if these adaptations could have good or bad consequences for the birds down the road, considering that urban environments aren’t going away anytime soon. It is also important to understand how to manage such environments for the birds that maybe aren't urban adapted.”

The full study can be found in the journal Global Change Biology.

Image © Shutterstock

Become a member or log in to add this story to your CPD history

Practices urged to audit neutering data

News Story 1
 RCVS Knowledge has called on vet practices to audit their post-operative neutering outcomes.

It follows the release of the 2024 NASAN benchmarking report, which collates data from neutering procedures performed on dogs, cats and rabbits.

The benchmarking report enables practices in the UK and Ireland to compare their post-operative outcomes to the national average. This includes the rate of patients lost to follow-up, which in 2024 increased to 23 per cent.

Anyone from the practice can submit the data using a free template. The deadline for next report is February 2026.

Visit the RCVS Knowledge website to complete an audit. 

Click here for more...
News Shorts
RCVS pays tribute to well-loved equine vet

The RCVS and the Riding Establishments Subcommittee has paid tribute to well-loved veterinary surgeon and riding establishment inspector, Rebecca Hamilton-Fletcher MRCVS.

Linda Belton MRCVS, RCVS President, said: "I, along with my colleagues on the RESC, RCVS Council, RCVS Standards Committee, as well as RCVS staff, was very saddened to hear of the sudden death of Rebecca, or Becca as we knew her, last week.

"She was a true advocate for equine welfare and in her many years on the RESC worked to continually improve the quality and consistency of riding establishment inspections, all in the interests of enhanced horse welfare and rider safety."