Those of you who have been watching our Burrowing Owl Cam may have noticed a change in the number of eggs in the burrow. This female laid her first egg on April 2. Unfortunately, she broke that egg the next day, so keepers gave her an unbreakable “dummy” (fake) egg to sit upon. She laid eight more eggs in the burrow—and did not break any more.
On Tuesday, April 23r, keeper staff candled the eggs inside the burrow. Candling is how we determine if an egg is fertile and progressing normally. We hold a bright light up to one end of the egg, and the light shining through allows us to see if there is an embryo and/or blood vessels inside. Candling is done very quickly and is not harmful to the eggs. Lucky for us, the combination of white-shelled eggs and a dark burrow make burrowing owl eggs very easy to see through. We are very excited to report that they have seven viable fertile eggs! We removed the dummy egg and one egg that was a very early embryonic death. We could be expecting hatches as early as the beginning of May.
One interesting note about burrowing owl nesting is that native owls will often bring mammal dung (usually cow) to their burrow. There are several reasons researchers believe they do this. One is to attract insects to their burrow to provide food for the growing chicks. Another reason may be to help control the humidity inside their burrow. Keepers put a couple piles of cow dung inside the owl enclosure just before the beginning of the breeding season. When we candled the eggs, we noticed the nice soft material you can see surrounding the eggs is actually cow dung!
Some of the other items the owls like to “decorate” their burrow with are leftover mouse parts from their diet and pellets (casts made up of indigestible parts of their diet, such as bones and insect shells). These items also attract insects to the burrow, so do not be alarmed if you start to see more insects inside the burrow—this is a good thing for the future owl chicks.
Kristina Heston is an animal care supervisor at the San Diego Zoo Safari Park.
I LOVE all of these beautiful animals and I very much appreciate how much effort you guys put in to save them. :!)
Congratulations on the successful hatching of the eggs!
Where do chicks go during the day? They’re getting so big.
Chicks are really growing. Counted 6, 5 seem about same size and 1 younger little one.
Very nice to watch cam. Keepers are doing great job! Also the parents.
Very neat. Saw at least 4 babies before she came back. Very fuzzy babies
I checked out the cam on my lunch today and the female was very busy rearranging things with her beak. I swear I saw bits of eggshell. She tossed out some dinner, kept moving around a little but never stepped aside so I could get a clear look. I checked back later, but she was settled down. I just checked again from home and I clearly see a piece of eggshell! So I would guess that Owlet #1 has hatched probably around 11 am – 11:30am today. I also want to say to the cam operator an awesome job finding the male this morning in all that grass!
Any chance that this blog will be linked to the cams like most of the others are? Thanks.
I will be sharing this with the Starr Ranch folks.
Hope to see the little ones soon!
Thank you so much for this fascinating update, Kristina. Wow, that close up view of the candled egg and then seeing it in the keeper’s hand gives me a good idea of just how small the owlets will be. I know that the adults are about 6″ tall and have seen them in the flesh. I just love owls of all kinds. I am looking forward to watching them hatch and grow up. Too bad the female broke her first egg but she has 7 now, so it is going to be a crowded nest!
I am also a long time viewer of the Starr Ranch Barn Owl cams and have seen all kinds of things. The best year was 2017 when 6 eggs were laid, hatched and 6 owlets fledged. This year has got to be the worst. We think the mother is a first-timer (or at worst completely clueless). She has been observed offering her babies whole prey, sometimes tearing it into pieces properly. Five were hatched, two died within the first week. Papa stepped up to the plate and had been bringing plenty of prey so we don’t know just what happened. But last week, a viewer watched Mama kill the smallest owlet, eat it and feed it to the remaining two. With plenty of prey stashed behind them. It is a tree cavity not a nest box so we just don’t know what is going on.
I am reporting what is going on here in hopes that they will come on over and see these wonderful little owls. Hopefully, these parents are experienced and we will see all owlets fledge.