Brent geese arrive at Strangford Lough

Every autumn, approximately 25,000 of these light-bellied brent geese leave their breeding grounds in Arctic Canada and travel to Ireland to spend the winter. Like their ancestors before them, most will arrive on the mud flats of Strangford to refuel on the nutritious eel grass that grows in abundance here.

Food for thought
‘The birds leave Arctic Canada in late summer, travelling across Greenland, stopping off briefly in Iceland for a quick refuel before arriving in Ireland,’ explains Strangford Lough Lead Ranger Hugh Thurgate. A few will arrive on our shores in late August, but the majority land in early autumn and the influx reaches its peak in mid-October.  

In 2020 on World Population Census Day, volunteers and rangers stationed themselves around the perimeter of Strangford Lough and began the count. This year returned a count of around 26,500 with about 6% identified as juveniles, meaning they were born in Arctic Canada this year and have made the journey to Strangford Lough. Based on this years count, we are hosting up to 90% of the global population of light-bellied brent geese from Arctic Canada at Strangford Lough. “As the autumn progresses into winter a lot of the birds will move across the island of Ireland and some will go as far as Spain and France. “The count this year has been much higher than last years, 21,000 geese were recorded in 2019, with about 24% being identified as juveniles, so we can attribute the rise in numbers to a successful breeding season in 2019” explains Countryside Manager Andrew Upton.  

Habitat management
At the moment the birds are doing well but as Hugh explains this wasn’t always the case. The population dipped to below 10,000 in the 1930s when zostera (eel grass) declined significantly due to a wasting disease, proving the vulnerability of the species and its reliance on this food source.

‘The role that the National Trust plays in the management of Strangford Lough is crucial to the survival of these birds,’ he explains. ‘Through careful habitat management we maintain the mud flats and protect the eel grass population from invasive species such as spartina (cord grass). If the eel grass can thrive, then the birds will continue to return and refuel on this high protein food source. We also raise public awareness of the threat to these birds from disturbance, particularly from dogs off lead.

The information we have collected over the years around the light-bellied brent geese is one of the longest data sets that exists at Strangford Lough. Of course, as Mount Stewart Ranger Toby Edwards reminds us “data is one of the biggest aids to the work of the rangers”.

‘The Trust also plays a key role in the management of the wildfowling activity in the area.  We work closely with the British Association for Shooting and Conservation (BASC) and the four local wildfowling clubs on a range of conservation projects. We have created refuges for the birds, issue permits and patrol the shoreline during the shooting period (Sept – Jan) to ensure wildfowlers adhere to the rules of the scheme on Strangford Lough.

A successful partnership
Thanks to a successful tagging programme which commenced in 2003 in association with the Wildfowl & Wetland Trust (WWT) we are well informed about the habits of these visiting birds including their average life span which is around 10-15 years, however they can live as long as 25-30 years. The birds’ pair for life and are totally loyal to each other, they also maintain a strong family bond with their young and tend to breed alternative years.

‘The birds that visit Strangford Lough are a unique ecological unit,’ Hugh adds ‘and thanks to the support of our members and visitors, we are protecting their habitat for generations to come.’