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Finding and recognising pellets

Pellets from owls are the easiest to find and study, particularly barn, tawny and little owl, if these live in your area. This guide will mostly concentrate on these, and the two commonest day flying birds of prey, the kestrel and sparrowhawk.

Finding pellets requires knowing a little about the habits of the bird. Most pellets are produced at the birds roosting place. These are the easiest pellets to find. Collecting pellets can be very time consuming at first, but once you have located the pellet stations, it is possible to collect material regularly over long periods. If you know the species of bird the pellets are from, the results from the collection will be much more valuable.

Barn owls frequently roost and nest in the shelter of farm buildings, especially older ones. They are also fond of very old oak and ash trees. Dense white droppings are often a good clue to the birds presence. Search on the floor or ledges beneath any available perch, especially where you can see the droppings. The pellets are easy to recognise. They can be quite large (30-70mm long), smooth and rounded. They are characteristically black in appearance (regardless of the colour of the prey it has eaten) often with a varnish-like gloss when fresh. They are very solid pellets, with the material highly compressed. They are also the best material for pellet studies. Many pellets are produced at the same site in the dry, providing a good supply. The bones they contain are remarkably intact.

Tawny owl is the commonest owl in Britain, although it is not found in Ireland. You will know from the calls at night if tawny owls are present. They live in wooded areas or even in towns if there are enough trees. Daytime roosts are usually close to a tree trunk, often in tall mature conifers. Search the ground within a metre or two of each likely trunk. Again, very white droppings may give a clue to the site. Tawny owl pellets are usually greyer and more obviously furry than those of the barn owl. They are medium sized pellets (20-50 mm long) with a bumpy surface. The shape is long and narrow, but irregular and they tend to taper at one end. They are far less solid than barn owl pellets, and often break into fragments as they hit the ground. Since they are in the open they weather quickly, and the bones may be very prominent. They often contain sand, which may indicate earthworms in their diet. Tawny owls change their roost site frequently. They may also produce some of their pellets while out hunting. This makes them much harder to collect in any quantity. The bones they contain are more damaged by digestion than those in barn owl pellets.

Little owls may be seen perching on the dead branches of trees in hedgerows, parks and similar places. They often prefer to roost in very old oak and ash trees and are particularly fond of old willow pollards. Little owls are not common in Scotland and do not occur in Ireland. The pellets are small (15-40 mm long), elongated and pointed at one end. They are very light, and if pressed, may either crumble or feel spongy. Colour and content vary with diet. They often show insect remains such as wing cases. Again, because they are out in the open, they will quickly become weathered. They can be confused with kestrel pellets.

Short-eared owls are rare birds, and their pellets can be very difficult to find. The best time is in the winter, when they hunt over coastal grazing marshes. It may be possible to find a pellet along the rough grassy embankment of a sea wall. They very seldom occur in Ireland because there are no voles. The pellets are medium to large (30-60 mm long) in size. They are elongated, rounded at one end and tapered at the other. They are grey with a slight sheen and very lightweight, but strong and dont break up as easily as many of the other pellets.

Long-eared owls are also rare birds, and so it can be very difficult to find the pellets. In the winter they often roost in thick thorn hedges or conifers in farmland, scrub and woodland edge. These roosts are often used traditionally year after year and can be shared with up to ten birds. Therefore, a large number of pellets may be found in one place. The pellets are slightly smaller than those of the short-eared owl. They are long, irregular and very slender. Unlike other brown owls they breed in Ireland.

Kestrel pellets may be found when searching for those of owls, and can be confused with little owl pellets. They can be found beneath the eaves of buildings and below pylons and dead branches of trees - anywhere where a kestrel might perch or roost. The pellets are distinctive. They are small (20-40 mm long), pale grey (when dry) and with a rather felty texture. They are also slightly flattened and pointed at one end. Kestrels, like other raptors, digest their prey more thoroughly than owls. Their stomach acids are stronger, which means that bones in particular are much less evident in pellets. They also tend to tear their prey up rather than swallow it whole. So expect to find fewer, more fragmented bones. Because they also take a high proportion of insect prey, kestrel pellets really require different methods of study from those described for owls.

Sparrowhawk is our most abundant day-flying bird of prey. Since they roost in trees, sparrowhawk pellets are often found when looking for owl pellets. They have regular plucking posts where they take their prey before eating it. These would be good places to look for pellets. The pellets are small and compact (25-35mm long), rounded at one end and tapered at the other. The main ingredient is feathers, but bones are only rarely found.