Ask an RSPB expert: your January questions answered

House Sparrows, Blackbirds, Starlings and Blue Tits: these garden visitors may be a familiar sight and could be the type of species you feel comfortable identifying. However, every year our Wildlife Enquiries Team receive some strange sightings of birds that can be a struggle to identify.  

One of the most common causes for confusion is plumage abnormalities. Sometimes these variations in feather colourings can prove tricky – turning many a well-known bird into a hard-to-identify puzzle! These variations include: 

• Melanism, in which the amount and/or distribution of dark-coloured melanin pigment is higher than usual.  

• Leucism, the absence of pigment cells causing birds to have white feathers, sometimes patches and sometimes the whole plumage.  

• Xanthochromism, an excess of yellow pigment. 

• Erythrism, in which a chestnut-red pigment replaces certain other pigments, leading to a more reddish appearance.  

Both erythrism and xanthochromism are quite rare compared with leucism and melanism. 

The most common type of plumage abnormality that our team is contacted about are birds that have leucism. These birds can have patches of pale or white feathers where they shouldn’t, or they can even have all white feathers.  

Leucism is different to albinism: it’s much more common and the birds aren’t pure white with red eyes. Instead, birds with leucism still have some kind of pigmentation on their feathers or other parts of their body, often on the legs or eyes, rather than a total absence of all pigmentation. A common example of leucism is when Blackbirds have a few white feathers on their neck. This kind of colouring can result in people mistakenly thinking they’ve seen a Ring Ouzel.  

So, if you see something that doesn’t fit with any familiar visitor, or you’ve searched through your bird ID books and can’t find a match – it may be a bird with a plumage abnormality.  

If you do spot one of these unusual birds, you can report the sighting to the British Trust for Ornithology Abnormal Plumage Survey. Through the survey, the BTO hope to understand which birds are affected most frequently, in what ways and where.  

Starling murmurations are one of winter’s most breathtaking displays and seeing one is an unmissable spectacle for bird enthusiasts. During the cold months, Starlings group together, taking to skies in flocks of hundreds, and sometimes even thousands, at dusk before settling down to roost. 

Moving together in synchrony, they form billowing cloud-like formations, as they swoop and dive, all whilst avoiding crashing into each other. There are more Starlings around in the UK at this time of year, as our resident Starlings are joined by migrant birds from Scandinavia. Some murmurations have reached tens of thousands of birds. The migrant birds usually start to leave the UK in February. So, it’s not too late to see a murmuration but January could be your last chance until next autumn.  

Murmurations typically take place at dusk as the birds prepare to roost together for safety and to share warmth. Starlings are vulnerable to predation, particularly with so many gathering in one place. The dance-like movement of murmurations helps to confuse predators, keeping individual Starlings safe.  

Some of the most famous RSPB sites for seeing these beautiful displays are RSPB Leighton Moss, Ham Wall, Minsmere and Fen Drayton Lakes nature reserves. However, we recommend checking before you visit, as the murmurations can move around.  

Starlings in the UK offer updates on the latest sightings: www.starlingsintheuk.co.uk.

Hibernation is one of nature's clever ways to keep animals going through the cold winter months and allows them to reduce their energy use whilst food is scarce and temperatures are low.  

Although it’s an effective method for dealing with the coldest season, only a small number of animals truly hibernate in the UK. The process is triggered by hormones and environmental factors such as daylight hours that cause the animal to enter a controlled state of hypothermia (the lowering of body temperature to reduce metabolic demand).  

Amphibians such as frogs, toads and newts will find shelter to hibernate in log piles, compost heaps or even underwater at the bottom of ponds. Bats, Hazel Dormice and Hedgehogs are the three mammal groups that also truly hibernate, along with certain species of ladybirds, butterflies, solitary bees, and wasps. 

Torpor is different to hibernation; this process is a short-term lowering of body temperature and metabolic rate and is used to conserve energy during spells of unfavourable conditions (such as low temperatures or a drop in available food). Torpor is only used for a few hours or days and acts as a more energy-efficient sleep. The animals do not need to build up large fat reserves in preparation, unlike the requirements of hibernation. Many more species exhibit torpor such as Badgers, squirrels, some reptiles and even young Swifts in cold spells.  

You can help hibernating animals by leaving garden leaf and log piles undisturbed, planting native, nectar-rich flowers for autumn, sweeping snow from frozen ponds, and melting a hole into the frozen surface with warm water daily to increase oxygen levels in the water. You can also set up hedgehog houses, bat boxes, a hibernaculum and bug hotels to create ideal shelters for a safe hibernation.  

I’m a massive nature lover and have been with the RSPB for the past six years as a wildlife advisor. I spend as much time as possible outside, whether that be walks, tending to my allotment or just sitting in my garden listening to birdsong. Getting my daughter interested in wildlife is a major passion of mine and I love talking to teachers or parents about nurturing children’s enthusiasm for the natural world.