- Author: Emily C. Dooley, UC Davis
Research shows land managers should clean nest boxes in autumn to avoid disturbing the raptors
When it comes to American barn owls, forget spring cleaning.
The best time of year to clean out nest boxes to ready them for breeding pairs is the fall months of September through November, according to research out of the University of California, Davis, that analyzed nearly a century of banding and other records.
In a paper published in the Journal of Wildlife Management, researchers found that the median egg laying date for barn owls (Tyto furcata) in California is Feb. 20, so cleaning nest boxes in the fall is recommended.
“The risk is you could disrupt a nest that has already started,” said lead author Ryan Bourbour, a Ph.D. candidate in ecology in the Department of Animal Science at the time of the study. “We want to reduce disturbances to nesting pairs even in the weeks prior to egg laying.”
American barn owls offer a natural way for land managers and agricultural operations to control pests, because the raptors eat mice, gophers and rats. One breeding pair can consume up to 2,000 rodents annually, according to the UC Davis School of Veterinary Medicine.
But natural tree cavities and old barn structures are not as plentiful as they once were, so installing nest boxes can attract the barn owls. And land managers who spend money installing these “nest box networks” have long asked about the best time of year to do maintenance and cleaning. Planning cleaning and maintenance well before the start of the breeding season is “part of making that nest box worthwhile,” Bourbour said.
Pellets add up
After eggs hatch, nestlings spend their early days eating and living in the nest boxes until they are able to leave the nest, said Breanna Martinico, another paper author and an animal science Ph.D. candidate in ecology.
The nestling period of roughly 65 days is considered long.
“That's two months where owls are living and growing exclusively in that nest box,” said Martinico, who is also a UC Cooperative Extension human-wildlife interactions advisor in Napa, Lake and Solano counties.
As many as five or six nestlings are typically in a box, and they eat up to four or five rodents each day. Nestlings swallow their prey whole, and what isn't digested — fur and bones — is coughed up in round or oval-like pellets.
“They're in there for seven to eight weeks just regurgitating these pellets,” Bourbour said. “A lot of pellets pile up over the course of a breeding season and a lot of these boxes need to be cleaned out.”
From anecdotal to data
Discussions about how early the breeding season starts have mostly been anecdotal. To get a better picture, the paper's authors analyzed 96 years of banding records from the United States Geological Survey Bird Banding Lab and 39 years of intake records from California Raptor Center at UC Davis. Both databases helped them estimate the typical egg laying time of year in California, Martinico said.
Having this information can help land managers ensure maintenance is done and nest boxes are safe for the next breeding pair, helping barn owl populations while also benefiting agricultural operations.
“We can give them tools to manage barn owl nest box networks effectively and maximize pest control through owls,” Martinico said.
Additional co-authors include Emily Phillips, Jessica Schlarbaum and Joshua Hull in the Department of Animal Science, Michelle Hawkins in the Department of Medicine and Epidemiology at the UC Davis School of Veterinary Medicine and Sara Kross from Columbia University.
Funding came from the National Institute of Food and Agriculture's Western Sustainable Agriculture Research and Education program.
The journal article is entitled Banding records of nestling barn owls reveal optimal timing for nest box maintenance in California.
/h3>/h3>/h3>- Author: Denise Godbout-Avant
With their complex social structure and “waggle dance” to inform hive members where food sources are located, honeybees are fascinating creatures.
But honeybees are not the only bees flitting about the flowers on our crops and in our gardens in search of nectar. There over 4,000 species of bees in California.
Other Bees
There are over 1,600 species of native bees in California. Unlike honeybees and Bumble bees, most are solitary in nature, and do not produce honey or wax for consumption by others. In North America, only the European honeybee and Bumble bees build hives and live in colonies.
There are 3 basic types of bee nesting:
- Ground nesting bees, which make up 70% of bees. Mining bees are an example of these.
- Stem and wood nesting bees, such as leaf cutter bees or mason bees, make up another 30% of bees.
- Colony nesting bees, such as honeybees and bumble bees make up less than 1% of all bees in North America.
Bees are in Trouble
Some ways you can help:
- Plant a garden full of flowering plants to attract bees and other important pollinators. Make sure you have something bloom during the spring, summer, and fall seasons.
- If you use a pesticide, choose one that is less toxic such as a horticultural soap or oil.
- Provide a space for nesting bees, with bee houses and bare patches of soil.
Upcoming Bee Talk
Date: Wednesday, September 14
Time: 3:15 – 4:15pm
Location: Modesto Junior College West Campus, 2201 Blue Gum Ave., Science Community Center in room 115
Denise Godbout-Avant has been a Master Gardener in Stanislaus County since 2020.
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- Author: Karey Windbiel-Rojas
I've had a few calls about raccoons recently; reports ranging from them getting into trash cans at night, to even a report of one coming through a friend's open kitchen window and licking the butter dish!!
Raccoon sightings are not new to residential areas. While they normally live in natural habitats, they can easily adapt and survive in urban settings where they may damage garden plants, knock over garbage cans or compost piles, and eat backyard fruits, nuts and vegetables.
Problems in and around the home can also occur when female raccoons look for nesting sites. They can cause damage by ripping off shingles and other structural features when trying to get into the attic or underneath decks. Odors and other issues may result once they find a suitable nesting site, too.
Raccoons are known to carry parasites and diseases so beware of contact with these animals by you or your pets.
If raccoons become a problem on your property, learn about your management options by consulting the UC IPM publication, Pest Notes: Raccoons.