American Barn Owls (Tyto furcata) are very different from their European cousins. Although they look similar, Barn Owls in North America are around 50% heavier, with males averaging 474 grams (over 1 lb), compared to just 312 grams (11 ounces) in Europe. Body shape is also different, with proportionally shorter wings and longer legs. Despite their weight, wing length is only 12% more than for European birds, while leg length is 25% greater.
In central and south America several different populations of Barn Owl occur, some of which are a good deal smaller.
Due to its larger size, the North American Barn Owl is able to take larger prey. While various species of vole, such as the Meadow Vole (Microtus pennsylvanicus) are commonly taken, American Barn Owls can also prey on Cotton Rats, Wood Rats, Ground Squirrels and Pocket Gophers. Generally speaking, they mainly take whatever kind of rodent is most available to them – and this is usually the most abundant.
Use for rodent control
In America, Barn Owls are increasingly being used in Integrated Pest Management (IPM) as an alternative to highly toxic rodenticides. Vineyards, rice fields, sugar cane crops, and orchards can all benefit from the installation of Barn Owl nestboxes. These are erected at a minimum density of one per 10 acres with up to 25 boxes per 100 acres in some cases. Here is a good example from a 40-ha vineyard near Sacramento, California.
It stands to reason that larger birds will require more nesting space and it is worth bearing this in mind when looking at the nestbox information we provide. For North American Barn Owls, the internal depth from the bottom of the entrance hole to the floor of the box, and the floor area, should be increased by about 30%. However, the hole size (5 x 5 inches) should not be increased as this may help protect the birds against larger predators such as Great Horned Owl.
Where boxes can be erected inside buildings, the timber does not need to be thicker – 3/8 or 1/2 inch will suffice. However, for outdoor boxes in extreme hot/cold climates 3/4 inch sheet material is sometimes used. However, please note that these will be significantly heavier and therefore more difficult to erect. Barn Owl projects in very hot climates (such as in Israel and in California) use pole-mounted nestboxes that are well-ventilated and often painted a light colour to aid heat reflection.
Where nest predation is an issue, the exercise platform may need to be omitted and sheet metal used to prevent predators climbing up to the box. Another option is to provide a polebox on a metal (rather than a wooden) pole.
In their first autumn, European Barn Owls settle into a home range where they spend the rest of their lives. However, in some parts of North America, Barn Owls migrate south to escape cold winter weather. This may be of importance when considering things such as wind turbines. A migrating Barn Owl is likely to be flying much higher than a foraging Barn Owl, and is therefore at greater risk of collision. Even so, based on the available evidence the risk is still considered small.
If you are considering keeping a captive-bred North American Barn Owl, you should consider the size difference when thinking about aviary size and food requirements. Increasing the floor area of the aviary by about 50% and the amount of food by a similar amount should be about right.
All mention of Barn Owl-related legislation on our website, whether it concerns wild birds, injured wild birds, or captive-bred specimens, refers to the UK only. In other countries, different national and/or state laws will apply. If a situation ever arises whereby legal issues are a concern, please seek advice on the relevant legislation.
Aside from a few isolated islands, there is only one species of Barn Owl in the Americas – the American Barn Owl Tyto furcata. However, some people still consider all of the world’s Barn Owls to be of the same species, Tyto alba. Because of this, North American Barn Owls are sometimes referred to as Tyto alba pratincola and sometimes as Tyto furcata pratincola. Don’t worry too much about the name, it’s still the same bird!