Feeding Time Lapse Video

Here is a project I started working on a few weeks ago. This video is a time lapse showing 16 feedings from the night of March 28-29. Neither Youtube nor anyone else on the Internet can handle portrait-oriented video, so unfortunately it is in a horizontal format and looks a bit offset. One day I'll learn about video programming. Enjoy it.

Three Hungry Mouths

We haven't yet blogged about the third hatch, which happened last Friday, April 22nd. Since then, there has been lots of activity. Tonight was the first night we noticed open eyes on the eldest owlet. They are not fully open, but the little owlet can definitely open her (or his) eyes. Most of the food brought in is geckos or lizards, with an occasional insect. Despite the drought, there seem to be enough insects to supply the reptile population, which in turn feeds the owls.
The weather has been quite warm, both by day and night. Despite the owlets being too young to maintain their own body temperature, Mrs. Owl has not had to incubate them much, due to the warm night-time temperatures. She thus has been spending increasing amounts of time either hunting or sitting in the doorway. During the day, she is often up on the perch or in the doorway, and even sometimes out of the box, as she was Sunday afternoon for over an hour.

Second Hatch

The second egg hatched sometime today. We haven't had time to figure out exactly when, but here is a dramatic family portrait. Mr. Owl sort of lost his balance and fell into the box while delivering a lizard. In the foreground is Mrs. Owl, 2 fuzzy owlets, and the remaining egg.

First Hatch!

Tonight, between 6:06 and 6:10pm, the first egg hatched! This is on the early side of the possible hatching dates at 28 days. Normal range is (28.5 to 32 days, 1 sigma). In the first photo, you can see the eggs at 6:05pm, with what is likely a small hole in the egg closest to the camera, which is the one that hatched. The second photo is at 6:11pm, just after hatching. You can see a shiny baby just to the left of Mrs. Owl's leg, and a partial eggshell. The third and fourth photos show a 1/2 eggshell, an unhatched egg, and the owlet. In the fifth photo, Mrs. Owl has picked up the eggshell and begun to eat it. She presumably does this to recover the calcium in the shell. In the sixth photo, you can see that the shell is completely gone. You only can see the two remaining eggs and the hatchling. In the 7th photo, about 2 hours after hatching, the owlet has dried out and has now become fuzzy.
Mr. Owl then began bringing food, consisting of (so far) a gecko, a couple of insects, and a Texas Blind Snake. In the last photo, Mr. Owl is bringing a blind snake while Mrs. Owl is still working on tearing up the gecko for the owlet. He came with the snake, stared down for a little while, and then started to leave. Mrs. Owl dropped the gecko, and went up to the entrance to take it from him.
As great as male owls are at hunting for the entire family during incubation, they are not very useful when it comes to domestic duties. They bring food, and if nobody takes it, they usually turn around and leave with it. We have observed this later in the nesting cycle, when the female is out hunting. The male will arrive with food, and if the owlets are too small to take the prey, the male will just give up and leave again. Often, the female will arrive soon after with the same item that she has presumably taken from the male outside the box.

Geckos Galore

Last night was a banquet for Mrs. Owl. She was brought 6 geckos and a lizard (last photo). Mr. Owl seems to be working very hard. Perhaps it was to make up for the previous night, in which nothing was brought between 9:28pm and 6:11am. And at 6:11am, it was only a small caterpillar. Earlier that night, 3 geckos had been brought in. So, last night's haul seemed to be at least twice as big as the previous night.
We have been rather neglectful at reviewing the pictures and posting updates. We will do this more frequently once the eggs hatch, which should be this week.

Reposting Feeding from 1 April

(reposting this entry, because the photos were cut off the first time.)
Mrs. Owl has stopped laying at 3 eggs, so that will be our clutch size this year. We have friends with owl box cameras who have 4 and 5 eggs this year, so all are in the typical range of 3-5. Food availability is probably the primary factor in their decision about when to stop laying, but there are probably a number of other factors. Last night was a busy feeding night, with 15 feedings, all of insects, apparently. The previous night there had been a bird, of a species we could not determine, and Mrs. Owl spent some time last night apparently feeding from it, as feathers were flying. We couldn't see for sure, because she cached it below the view of the camera. Mrs. Owl has been taking very short evening and morning breaks. This morning's break was only 6 minutes, around 6:30am. Included today are some feeding shots. The first two show a moth, as does the 4th. The 3rd shows a caterpillar. The male seems to come down into the box more than we have seen in the past. One afternoon, he came with an insect at about 6:20pm (90 minutes before sunset), and stayed in the box for nearly 2 hours until dark, mostly sitting in the entrance hole. He must have found a target of opportunity by chance, and come with a daytime feeding. So, now that Mrs. Owl spends nearly 24 hours in the box, we are getting good looks at Mr. Owl.

Three Egg Night

Sometime this afternoon, Mrs. Owl laid her third egg. Though it is hard to tell exactly, it was likely laid between about 12:30 and 1:20, when she sat very still. She spent most of the day incubating the eggs or preening her feathers. So, the eggs are developing, and the young will likely hatch on different days. Mrs. Owl took a shorter evening break than she has in the past, only 15 minutes, so she is getting serious about incubation.

More egg photos

Two Eggs!

Sometime between 10:54 and 11:10pm Mrs. Owl laid her second egg. This is our first view of it.

Heat and a Night Out

Mrs. Owl is in the box again this morning after nearly 12 hours out of the box last night. She was gone from 7:52pm to 7:14am. The first photo shows her returning through the entrance hole. Thus, we didn't observe any feedings at all last night.
Yesterday was quite a hot day (87 degrees), and Mrs. Owl spent the afternoon off the egg, mostly with her wings spread for coolness. She also panted, using a motion called "gular flapping" in which her throat pulses with her mouth open to help cool her down. She spent some time in the entrance hole, looking out into the sun.
We haven't noticed the ants at all in the last day. My guess is that they probably were attracted to any mucus or smell that may have been on the egg when it was freshly laid. Now that it is just a dry egg, they have no more interest, and have gone back to whatever they were doing before the egg was laid. In any event, Mrs. Owl seemed to pay no attention to them when they were there, and doesn't in any way seem irritated.
This morning, she seems like she is settled on the egg, so perhaps she is either beginning ot incubate it, or is perhaps pondering her second egg, which is due today. Typical clutch sizes are 3-4 eggs, but they can number as few as 2, or as many as 6. More experienced owls tend to have larger clutches, probably because they are capable of finding more food.

Snakes and Ants

Mrs. Owl was out all night, from 11:03pm to 6:55am, returning with a gecko in her mouth (first photo). Shortly after, she was delivered a second gecko by her mate (2nd photo).
We've read a bit more on Acrobat ants, and it seems that they are quite compatible with Owls. According to Fred Gehlbach, the world authority on Eastern Screech Owls (he wrote the book on them), Acrobat ants often do live in Eastern Screech Owl nests, and can deter predators. It is a tradeoff, however, as they will eat any cached food.
Gehlbach writes:

Acrobat ants, though, live in occupied boxes and cavities. Their brood (larvae, pupae) is housed in damp nest debris...They sting and spray me but not the owls and bite pieces out of food caches, removing these to their brood, often out of reach of the owls...Such symbiont competition could be severe, if Texas blind snakes did not reduce the numbers of at least some insect competitors, and my limited observations suggest they do....

Texas blind snakes are an earthworm-sized snake that is prey for the owls, but as they are slippery, they sometimes get away in the nest box. In this case, they often set up residence in the nesting material, out of reach of the owls, and feed off insects and larvae in the nesting material.

Gehlbach continues:

But there is a possible tradeoff in the owl-snake-ant symbiotic "triangle." Although the snakes are beneficial in removing ant brood, acrobat ants may protect the owls by attacking potential predators. If ants are indeed displaced by blind snake predation on their brood, the protection disappears. Which is mor important, reducing or eliminating and competition for cached food or cohabitation by the ants and hence their protection? Right now I cannot say, but I have noticed that flammulated and western screech owls are also apparently protected by cavity-cohabiting ants that do not disturb their owlets.

In our nest box, we have observed relatively little cached food during the season. About 3 times per season, something big, like a rodent or bird, will remain in the box for about a day while it is consumed, but most of the rest of the food is consumed within minutes after it is brought in, so the ants would have no effect on it. In Gehlbach's book, I have read accounts of significant food caches of perhaps even more than 1 bird or rat at a time. Our owls seem to subsist mostly on geckos, lizards, cockroaches, and other insects.

1st Egg Laid

Mrs. Owl laid her first egg sometime between 11:15 and 11:40am on March 22nd. She didn't really incubate it much, and spent time standing over it. Eastern Screech Owls generally start incubation with the second egg, which should be laid around the 24th.

Another interesting puzzle we have is that Acrobat Ants seem to have showed up, and are crawling over the egg. We have had Acrobat Ant infestations before, but never so early in the season. Usually we notice them near the end of nesting. And we have never seen them on the egg. While Acrobats don't bite, they can compete with the owls for stored food. So we'll have to keep an eye on this situation to determine whether there is anything we ought to do. So far, it hasn't seemed to bother Mrs. Owl in her dealings with the egg.

FIrst Evening in the Box

Mrs. Owl spent her first evening in the box, looking out the window and watching the world (and Cardinals) go by. She spent the whole day in the box.