The continued cold weather has prompted Scottish Natural Heritage to remind people using the countryside to give wildlife space to feed and survive.
Last winter a wide range of species suffered, including common birds such as wrens, dunnock, treecreeper, robin and greenfinch.
Barn owls also suffered.
And if the weather continues to be as cold as it has been recently then a similar situation could arise this year.
The frozen conditions mean wild birds, particularly those species which rely on wet habitats such as ducks, geese and shore waders, are likely to be struggling to find sufficient food to survive.
There have been reports of unusual wildfowl behaviour, such as mass movements away from traditional wintering areas, and some waterfowl and other birds are under serious pressure due to poor feeding conditions.
There is limited evidence that some coastal waders are losing body condition.
Confusingly, others seem OK but it is early in the season and hard weather usually has more of an impact later in the winter.
Some wildfowlers have reported small numbers of geese in poor condition, though most seem to be coping.
Other species such as snipe and woodcock have headed west, where there is less snow and the ground is not as frozen. As well as moving around species often move into gardens.
This means people are likely to see more unusual visitors such as water rails and woodcock.
Dr Andy Douse, SNH senior ornithological adviser, said people can help by avoiding getting too close to wildlife at this time and by providing food for birds in gardens.
He added: “The continued severe cold weather throughout much of Scotland is prolonging the risk to many species, particularly birds. They will need all their energy to keep warm and find food.”
Meanwhile the sustained cold weather is expected to lead to an unprecedented extension of the current suspension of wildfowling. SNH staff will be assessing the state of inland and coastal wetlands and receiving reports of waterfowl numbers and condition from different locations across Scotland.
The Scottish SPCA has also urged members of the public to call its animal helpline if they find a hedgehog during the freezing winter weather.
Staff at the charity’s Wildlife Rescue Centre in Fife are caring for 84 hedgehogs, some of which have arrived weighing around a third of their ideal body weight.
Centre manager Colin Seddon said, “Hedgehogs should be hibernating by now but there will some out there who won’t survive without help.
“If anyone finds a hedgehog during this spell of bad weather they should try to contain it by picking it up using gardening gloves or a thick towel and placing it in a secure box.
“It can then be left with fresh water and tinned cat food until it can be collected.”