Ranger Martin Hind captured this image of a bat in Dingwall
Bats found lying on the ground and being mobbed by birds flying in daylight could be linked to extreme hunger, an expert has said.
Anne Youngman, the Bat Conservation Trust's Scottish officer, said the handful of incidents may be related to last year's poor summer and autumn.
She said it was too early to tell if the problem was more widespread.
Last year, adult bats were reported abandoning their young as they struggled to cope with bad weather.
Mrs Youngman, who will travel from central Scotland to lead a bats workshop in Strathpeffer Community Centre, near Dingwall, on Thursday, said the first bats of the season were emerging from hibernation.
She said: "Down here in the central belt people have found grounded bats which were very weak and very hungry.
"This may be a reflection of last summer and juveniles not getting enough food to build up fat to survive through hibernation."
Mrs Youngman said she knew of only a couple of incidents so far, but she added: "Someone visiting Mull reported seeing a bat flying during daylight and mobbed by birds.
"For bats to be flying in daylight is something strange and you don't normally see and could mean the bat was really hungry."
In day time bats run the risk of falling prey to other animals and it has been known for them to be mobbed and eaten by crows.
She advised anyone finding a bat in difficulty to contact the nearest conservation officer, or the Scottish Society for the Prevention of Cruelty to Animals.
Hungry bats are often revived on meal worms, or the jelly from dog or cat food finely chopped up.
During Thursday's workshop, Mrs Youngman will help people on how to identify common species found in the Highlands.
On 17 May, a workshop will be held in Contin Village Hall on red squirrels.
Conservationists are concerned for native reds following the first confirmed sighting of a grey squirrel in the Highlands.
The non-native species competes with reds for food and carry a virus fatal to the smaller animal.
Highland Council countryside ranger Martin Hind said: "These workshops are open to anyone who is interested in learning techniques to identify, record and learn more about the wildlife found on their doorstep."