With spring nearly upon us, it is once again the time of year when birds begin to nest on Therfield Heath.
The Conservators of Therfield Heath and Greens are advising anyone walking on the heath to be aware of ground-nesting birds, and to take care not to disturb their habitats.
Birds nesting on the heath include skylarks and meadow pipits, which have been singing on the heath and will now start to nest.
A statement from the conservators said: "We understand Therfield Heath is a great place to walk and to exercise your dogs, but please, please consider the inhabitants of the site.
"Wherever you are on site, there are likely to be some skylarks and even rarer meadow pipits trying to nest in the longer grass.
"The easiest way to help these birds succeed is by keeping to the obvious pathways and keeping your dogs with you on those tracks.
"Repeated disturbance by dogs that run through the grass, and those that specifically 'quarter' such as spaniels, causes the birds to abandon their nests - it may be the eggs or the young that they abandon, but it will lead to a breeding failure."
Disturbance of the nests could lead to birds failing to nest, eggs failing to hatch, chicks dying from cold or lack of food and nests becoming vulnerable to predators.
A recent survey by the conservators found ground-nesting birds almost everywhere across the site, but that there are some areas with a higher density than others.
As the birds are already under threat, visitors to the heath are reminded to be mindful of the risk of disturbing nests at least until the end of the breeding season at the end of July.
When birds are in distress, they will make a repeated alarm call and will approach people much more closely than they would normally - potentially even dive-bombing. They may also feign injury in an attempt to distract people from their nests.
Conservators are going to put up signs around the areas with the highest density of nesting birds, but hope that the public will still remember to be careful in areas with a lower density and keep to the path with their dogs.
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