Barn owls (Tyto alba) are medium-sized owls with distinct heart-shaped faces that have been embraced by farmers for their rodent-hunting abilities. As nocturnal predators that feed primarily on small mammals like mice, rats, voles and gophers, barn owls provide free pest control by naturally reducing rodent populations that can damage crops and spread disease. Farmers across the world have found that encouraging barn owls to nest and roost in barns, silos, and other farm structures through the installation of nest boxes helps control rodent infestations and minimizes the need for chemical rodenticides.
Why are rodents a problem for farmers?
Rodents like mice, rats, voles and gophers can cause extensive damage to agricultural operations. These small mammals feed on crops both pre- and post-harvest, contaminate food supplies with their feces and urine, and spread diseases. Some key problems caused by rodents on farms include:
- Consumption and contamination of crops – Rodents will eat newly planted seeds, ripening fruits and vegetables in orchards and fields, and nibble on stored grain. Their urine and feces contaminate food supplies.
- Structural damage – Rodent burrowing and gnawing can undermine building foundations and lead to structural collapse. They will chew on pipes, wires and wood.
- Disease transmission – Rodents can carry many diseases transmittable to livestock and humans, including salmonella, leptospirosis, Lyme disease, hantavirus and the plague.
- Loss of inventory – Grains, animal feed and other inventory will be damaged or have to be thrown out due to rodent infestation and contamination.
Rodent infestations if left uncontrolled can result in extensive economic loss for farmers through decreased crop yields, spoilage of inventory, and repair costs from structural damage. Rodents reproduce rapidly, so proactive control is crucial.
How can barn owls help control rodents on farms?
Barn owls are voracious predators of rodents. A single barn owl family with 5 owlets will consume about 3,000 rodents over the course of a summer, making them highly effective natural pest control (Table 1).
Barn Owl Family Size | Rodents Consumed Per Summer |
---|---|
2 adult owls | 1,500 |
2 adults + 5 owlets | 3,000 |
Key reasons barn owls are so valuable for rodent control on farms:
- A barn owl can eat up to 1,000 rodents per year, averaging around 3-7 rodents per night.
- Their flight and hunting style allow them to navigate farm structures easily to hunt.
- Rodents made up over 90% of the diet of barn owls studied on farms.
- Barn owls will continue hunting even when rodent populations are low.
- They do not use toxic chemicals that can persist in the environment like rodenticides.
Simply by following their natural predatory instincts, barn owls provide an organic, sustainable method of suppressing rodent pests. Encouraging barn owl nesting is a win-win – the owls get needed nest sites and nourishment, while the farmers get free rodent control.
How can farmers attract barn owls to their farms?
Farmers can take the following steps to encourage barn owls to take up residence and provide natural rodent control:
- Install owl nesting boxes in barns, silos, sheds or under eaves of other structures. Be sure to site them 10-15 feet high with a clear flight path.
- Leave openings and perches in barns and similar structures for owls to enter and hunt from.
- Put up owl perch poles or boxes in fields. Owls hunt more effectively from perches.
- Leave dead tree snags standing – owls use natural cavities for nesting too.
- Avoid pesticides that may accumulate in prey and poison owls.
- Tell farmhands not to disturb any nesting or roosting owls.
Making the farm welcoming and safe for owls is key. One family of barn owls can make a big difference in keeping rodents under control over summer months when prey is plentiful.
What kind of habitat and nest sites do barn owls need?
Understanding the habitat and nesting preferences of barn owls will allow farmers to best provide for them:
Hunting Habitat:
- Open areas for hunting – fields, pastures, orchards.
- Grasslands and agriculture are preferred hunting grounds.
- Access to structures for roosting and nesting.
- Nearby water sources like ponds, streams or wetlands.
Nesting Sites:
- Cavities at least 4 inches wide x 20 inches deep.
- Old building ledges, abandoned burrows, hollow trees.
- Human-made nest boxes are readily used if sited appropriately.
- Tunnels in haystacks or silage piles.
- Undisturbed nests are critical – barn owls are very easily stressed.
Ensuring good habitat and nesting sites are available will encourage barn owls to become long-time residents and provide ongoing rodent control.
What risks do barn owls face and how can farmers protect them?
While highly beneficial for controlling rodents, barn owls face a number of risks requiring farmers’ care:
Threats:
- Use of rodenticides – poisoning from treated rodent baits.
- Vehicle collisions – often hunt along roadsides.
- Habitat loss from development.
- Climate change disrupting prey populations.
- Electrocution on power lines.
- Human disturbance of nests.
Protection Strategies:
- Avoid or limit rodenticide use – promote natural control.
- Erect road signs alerting drivers in owl areas.
- Preserve natural habitats on farms.
- Install barns lights to attract prey and pole covers to prevent electrocution.
- Protect and avoid disturbing nests, especially during breeding season.
Simple efforts to protect barn owls and their habitat ensures they will thrive and provide natural rodent control for generations.
What is the barn owl’s life cycle and breeding biology?
Learning barn owl breeding biology helps farmers provide for them during critical periods:
Breeding Season:
- March to September peak, though can vary by climate.
- Will have 2 broods per year in optimal conditions.
Eggs & Owlets:
- 4-7 eggs laid, incubate for 30-34 days.
- Owlets hatch asynchronously over a few days.
- Fledging occurs at around 8 – 10 weeks.
- Parents continue care until 3 months.
Hunting for Owlets:
- Can consume up to 250 rodents per month when feeding owlets.
- Must hunt almost continuously, mostly within 1 km of nest.
Supporting barn owls during breeding and rearing of young is crucial. Ensuring undisturbed nests and ample prey availability results in another generation of superior rodent hunters.
Examples of barn owl boxes and habitat management
Here are some examples of how farmers are installing owl boxes and managing habitat to benefit barn owls:
Owl Box Design Tips:
- Made of untreated rough-cut lumber to allow claw grip.
- Entrance hole at least 3 inches diameter, place 8-15 feet high.
- No perch, deep litter inside, recessed from entrance.
- Mount boxes on poles or building walls.
Barn Owl Box Program – Texas:
- Texas A&M NREC provides low-cost owl boxes.
- Also advice on placement and managing habitat.
- Helped establish barn owl populations across the state.
Operation Barn Owl – UK:
- Network of over 700 nest boxes on farms across Britain.
- Monitors populations and provides research on owls.
- Expanded owls’ range and increased populations by 30%.
Successful programs show that simple, well-designed nest boxes in optimal habitat can expand barn owl populations and boost natural rodent control.
Conclusion
Barn owls are powerful natural allies for farmers seeking to control rodent pests. By providing nesting and roosting sites in boxes, barns or other structures, farmers can encourage barn owl settlement and receive free, effective rodent control in return. Establishing protected nesting areas, managing habitat for hunting, and taking precautions against risks such as rodenticides will help maintain thriving barn owl populations. A resident family of barn owls sustaining themselves on farm rodents is a sustainable win-win for both the owls and farmers. Taking steps to welcome these remarkable raptors leads to a local, natural solution for controlling destructive pests.