Today we are highlighting Lisa’s Barn Owl nesting box in Bel Marin Keys. In 2020, the box had a pair of adult Barn Owls who successfully raised four owlets. 2021 was a different story, but we hope to share what we learn as we await test results from CA Fish and Wildlife. Below is the start of the nesting timeline. Lots of great photos and videos are in our news feed on Facebook!
2/21/21 – A male owl sings his song to lure a female partner.
2/24/21 – A female owl joins him, they begin to preen one another.
4/4/21 – The first egg is laid, and another egg is laid every 2 days. Totaling 4 eggs.
5/7/21 – The first egg hatched.
5/9/21 – Another egg hatched.
5/12/21 – The remaining 2 eggs hatch.
5/15/21 – The male owl is not seen on the camera again. The female owl begins to hunt and leave the owlets alone in the box.
When dad went missing, Lisa contacted All About Owls for advice. At this point, we began monitoring the situation to make sure that mom could catch enough food to feed all four chicks. Once it became obvious that mom was not able to provide enough prey for the four chicks, we advised her on how to discretely drop off supplemental food items for the nesting box. Please always check in with your local wildlife rehabilitation hospital before feeding a wild animal. (Special thanks to Petfood Express for providing Lisa a discount!)
6/2/21 – The smallest owlet passed away. While sad, it is not unusual for the runt of the owlets to not make it. There are many babies to feed, and the smallest one can’t always get to the food before their siblings gobble the food up.
6/27/21 – A second owlet passes away.
7/11/21 – The eldest owlet who was nearly old enough to fledge (leave the nest box) passes away.
This is very alarming to lose three of the four owlets, so Lisa and AAO got in contact with CA Fish and Wildlife to see if they can offer any testing to find out what happened to this owl family. The eldest owlet’s body was shipped to CA Fish and Wildlife’s lab for necropsy and rodenticide testing to see if we can get more answers.
8/25/21 – The last remaining fledgling owl is hunting well on his own! We were able to discontinue supplemental feedings at this time. Though it was sad to lose three of the four owlets in this nest, we are thrilled that this owl has made it to this stage successfully!
In early September the CA Fish and Wildlife test results were in: the cause of death was determined to be starvation. The extreme heatwave that occurred during the nesting period likely contributed to the death of this owl. This season has been tough for many young raptors because of the extreme heat that has occurred during nesting. These juveniles can easily become overheated and fledge too early to try to escape the heat in the nest. The heat will also affect the adults by reducing the amount of time they can forage for prey. Also, the prey likely becomes less active went it’s so hot. Unfortunately, this pattern has become more common in recent years.
Climate change continues to be a challenge for wildlife. By providing a nesting box for wild owls, we have a responsibility to make the nesting box as safe as possible by providing plenty of ventilation, floor space, and an installation location safe from predators and in the shade to protect from the heat. This nesting box was replaced with a larger vineyard-size nesting box, and additional panels were added to provide more protection from the heat for future owl families.
All About Owls is always here for any questions you have about wild owls, owl box installation, and to provide high-quality owl nesting boxes.