Australia is home to five different species of Corvid (ravens and crows). However, because of their physical similarities, i.e. their size and colour (black), they are difficult to tell apart. Another thing that crows and ravens have in common is that they are noisy, bold and incredibly intelligent. Therefore, if a murder of crows takes a liking to your roof, murder might very well be at the forefront of your mind.
Not only do they have an annoying habit of cawing early in the morning, but they can damage roofs, devour your fruit and attack your children and pets.
Despite their obvious faults, however, crows and ravens are protected by the Nature Conservation Act 1992 which means that harming, trapping or disturbing their nests is illegal.
If a group of crows have invaded your roof, it isn't because they wish to make your life a misery, though you might think so. There are several reasons they could be up there being a nuisance.
Grit for Their Stomachs
Many species of birds eat small stones and grit to help them to better digest seeds and other hard foods. Asphalt shingle roofs contain small pieces of sand and grit. After feasting on some nearby seeds then, your asphalt roof is not only a safe roosting spot, but it also provides them with a supply of grit.
Crows have also been known to pull up roof tiles and insulation in order to build a nest within a roof space. If it is spring and a pair of crows is tearing at your roof, they could be trying to build a nest.
Baby Birds and Eggs
Other birds too, such as house sparrows and myna birds, may have already established a nest within your roof. This could be what the crows are attempting to get at, as crows are known to eat the eggs and young of other birds.
Seeds too can quite often be found on roofs, dropped there by birds passing overhead. If the seeds have become lodged between the tiles, crows will quite happily tear the tiles away to get to them.
You May Need a Professional
Since crows are as intelligent as apes, according to research, getting rid of them may prove to be quite a challenge. With this in mind, you should probably seek the help of a reputable pest control service as they have the tools and the experience to send your Corvid squatters packing.