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Aug 1 - There has been little research
to suggest that barn owls migrate to warmer climates in winter.
Most nest and spend winter in the same area, which is likely with this
California pair.
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July 27 - It is easy to see why barn
owls were once associated with ghosts and hauntings. Imagine
candlelight illuminating this face, glaring down at you from the dark
rafters of an old barn!
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July 22 - It looks like a hot day in the nest box. The owls pant to stay cool in the heat.
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July 20 - Though the adults continue
to roost in the nest box, at this point it is unlikely that they plan
to start another brood this year.
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July 16 - The young barn owls are
probably far away now--once they leave the box, barn owl siblings
disperse in all directions for up to 2000 km (over 1200 miles) to find
their own territories.
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July 15 - The male stares blearily at the camera from his usual place in the nest box.
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July 12 - The barnowls' facial disks are very round when they are relaxed, but turns heart-shaped when they become alert again.
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July 9 - The barn owl's ears are set
at slightly different levels on each side of its head, and one is
directed slightly upward while the other points slightly
downward. This allows them to pinpoint the origin of a sound the
most accurately of any animal tested.
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July 8 - The ridge of feathers down
the middle of the barn owl’s face divides the facial disk into two
dishes. They collect sound waves and funnel them to the ears,
giving the barn owl its remarkable hearing abilities.
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July 5 - The pair continue to preen each other and roost together.
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July 3 - Barn owls are an excellent,
natural way to control rodent populations in an area. This shot
gives us a good idea of many rodents' last view of the world.
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July 2 - It's another quiet day in the nest box for the owl pair.
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June 30 - This is the first mating
event caught by the camera since the chicks fledged. Perhaps we
will see another brood this season!
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June 29 - A quick peck on the cheek
for the female--literally. The young owls may already be
searching for their own future nest sites.
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June 28 - The male stares wide-eyed at the camera, making his face look even rounder than usual.
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June 27 - The female vocalizes a few
times in the nest box. Barn owl sounds range from soft "snores"
and twitters to harsh, gargling screams.
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June 24 - The male and female take up their customary roosting positions for the day.
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June 22 - Preening each other and roosting together strengthens the parents' pair bond before the new nesting season. |
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June 21 - It is possible that the
parents are preparing for another brood--over 50% of pairs have been
known to produce a second brood in CA.
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June 20 - The three young owls seem to be gone for good. These two owls preening each other are the mom and dad!
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June 19 - The sun rises to find an empty nest box today, though two owls were in the box last night.
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June 15 - There have been two owls in the box lately, and they appear to be the same ones every time.
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June 14 - The barn owls are not the only ones living in this box!
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June 13 - All the owls are successful hunters now. Here, one is about to gulp down this rodent.
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June 12 - At least two of the owls stopped in the nest box several times tonight.
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June 11 - Two of the young owls were
absent from the box today and yesterday. They are all spending
less and less time in the box as time goes on.
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June 10 - This owlet pauses after
scarfing down a rodent. All three owlets continue to use the nest
box as a rest stop during the night.
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June 9 - The barn owl's large wing
area compared to its weight allows it to carry heavy loads, such as
large prey, at slow speeds.
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June 8 - Sibling rivalry is generally at a minimum among barn owls, as these three have clearly demonstrated.
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June 6 - This owl looks like he's never seen the camera in the box before!
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June 5 - The parents will feed their
owlets for the last time when they are 12-13 weeks old, which will be
in the next two weeks.
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June 4 - When these owlets finally
leave their parents' territory in mid to late summer, they will wander
through early winter until they find their own territories.
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June 3 - This barn owl takes a stretch before heading out for the night.
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June 2 - The young owls are now
virtually indistinguishable from the adults, though it could take more
than three years for their adult plumage to grow in fully.
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June 1 - Young barn owls tend to roost together for many weeks after they fledge.
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May 31 - You can see how much the
youngest owlet's face has changed in just the last 4 days! The
nest box has been empty more and more lately.
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May 30 - This is the youngest owlet again, practicing pouncing on a food item in the box before gulping it down.
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May 28 - The youngest owlet proudly stretches its wings after returning from another adventure outside.
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May 27 - Though still obviously the baby of the family, feathers are quickly replacing the youngest owlet’s fluffy down.
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May 26 - All three owlets were out of the box tonight!
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May 25 - Two of the owlets preen each other, just as we've seen their parents do before.
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May 24 - There seems to be something
of interest on the floor of the nest box--all three owlets are craning
around to get a glimpse of it.
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May 23 - The youngest owlet pesters
one of its siblings, perhaps hoping for a bite of food. Older
owlets have been known to feed their younger nestmates, though
apparently not this time.
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May 22 - The youngest owlet, easily
distinguished by its retention of downy feathers on its belly, remains
behind in the nest box during the evening hours.
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May 21 - The oldest owlet--shown
consuming a large rat--is about 10 weeks old. It is possible that the
owlet captured this prey without parental help.
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May 20 - Moving left to right, the owls are in the box from oldest to youngest.
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May 19 - We can expect even more pellets today after this big meal!
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May 18 - Mouth agape, the central owlet seems to be coughing up a pellet.
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May 17 - It's been about sixty days
since the first owlet hatched. As his nightly forays become more
regular, the eldest owlet should be able to procure his own meal by
about day 72. His curious glances at the camera have become more
frequent, perhaps indicating an urge to explore.
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May 16 - The youngest owlet gives its wings a stretch, indicating that he or she is "eager" to fledge along with its siblings.
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May 15 - We suspect that the oldest
two owlets have begun to explore life outside the box in short, early
morning jaunts. However, they continue to spend most of their time
within the box.
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May 14 - The central owl in this shot
shows just how dramatically owls can contort their necks. If you look
carefully, you'll notice that the owl's beak is pointing straight
upwards.
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May 13 - The mesoptile plumage of the
young owl in the foreground has been completely shed, save for around
his face, which makes him look as though he were wearing a shaggy mane!
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May 12 - An owlet flexes his impressive 42 inch wingspan.
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May 11 - Once the eldest owlet
fledges, or leaves the nest box for the first time, he will continue to
roost in the nest box during the day for several weeks.
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May 10 - Though they no longer venture
in front of the camera, the adult Barn Owls are still crucial to the
survival of the youngsters, for they continue to supply all the food
through the nest box hole. The adults also continue to ward off
predators.
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May 9 - In the background the two
eldest owlets squabble over a piece of food. Once they leave the nest
these owlets will be in direct competition with one another for
territory and food.
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May 8 - The eldest chick flexes his
wings, which are now almost entirely without mesoptile fluff. It is
thought that this flexing helps the juvenile plumage to slough off.
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May 7 - Who's the biggest in the
birdhouse now? The two eldest chicks are now losing weight as they
assume adult size, but the youngest chick is still in the "overshoot"
stage, meaning that for a few days at least he will be the biggest in
the box.
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May 6 - It must be a relief for the
owlets to lose the mesoptile plumage - today's temperature in
California was in the mid-80's (Fahrenheit)!
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May 5 - An owlet stares into the camera. Notice how fully the feathers of the facial disk have come in.
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May 4 - Remember when mom used to tend
to the nest in this corner and dad used to roost stolidly up front?
Those days are long over, as is evidenced by the size of these
youngsters, which is already starting to overshoot that of the adults!
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May 3 - This is another excellent shot showing the gradual loss of the mesoptile (white, fluffy juvenile) plumage.
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May 2 - The eldest owlet is beginning to show adult tail and back feathers as his prebasic molt progresses.
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May 1 - Scattered around the
foreground you can see many owl pellets (wads of coughed-up rodent
parts). For nest cleanliness, many of the pellets are trampled out the
nest box hole.
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Apr 30 - An owlet stares into the
camera. Like all owls, Barn Owls' eyes are immobile, hence the need for
an extremely flexible neck that can swivel almost 360 degrees.
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Apr 29 - The out-stretched wing of the
eldest owlet reveals his gradual acquisition of adult (basic) plumage.
This gradual change in feather composition is known as the prebasic
molt.
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Apr 28 - The owlets loaf about in the
nest box as central California enjoys a balmy, seventy degree day.
Curiously, the owlets will often keel over on their sides to rest.
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Apr 27 - Here an owlet exercises his wings. The day the owlets will fledge is fast approaching.
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Apr 26 - Dangling from the beak of the eldest owlet is a rat that looks a quarter of the bird's size!
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Apr 25 - Viewable is some rough- housing in the nest box as the young stretch wings and ruffle feathers.
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Apr 24 - This shot is ambiguous - are the young squabbling over food or feeding each other? Both can occur.
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Apr 23 - This unusual shot shows the
eldest sibling either preening or feeding the youngest. The phenomenon
of siblings enhancing each other's survival might have several
evolutionary advantages, including maintenance of sufficient nest box
heat once the parents begin roosting elsewhere.
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Apr 22 - Though it looks like mom is
feeding them, the youngsters are actually fighting to tear dinner from
her beak. They are quite capable of feeding themselves at this stage.
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Apr 21 - After a scuffle for food, the
youngest surviving chick is left knocked-over on his side. Fortunately,
he soon regains composure of himself. Life is hard for a young Barn Owl!
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Apr 20 - A viewer from Amsterdam recently sent us some
photos from April 12, the day the fourth chick died. The top
image shows the siblings consuming the fourth chick.
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At about 10am (middle picture), it appears that the
female is trying to feed the dying chick. In the bottom image, taken
just after midnight, the chick isn't looking very healthy. |
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Apr 20 - Although still clad in some
juvenile fluff, the chick seen here is giving his developing wings a
first stretch. He still has about twenty days before his first flight,
however.
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Apr 19 - The eldest chick devours a
mouse on his own. The voracity with which the chicks eat keeps the
adults busily catching food night and day.
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Apr 18 - We are now certain that only
three of the five Barn Owl chicks have survived. Once the two youngest
chicks died, they were eaten either by their nestmates or by the
adults.
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Apr 17 - A young Barn Owl looking very well-fed. The chicks will actually overshoot the adult in size before fledging.
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Apr 16 - A visitor to the site sent in
this endearing shot of a young Barn Owl (foreground) and its mother.
You can see that the contour feathers of the facial disk are starting
to come in nicely.
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Apr 14 - The male has sought refuge in
the nest box all day, contrary to the last couple of days. This might
be due to the violent rains California has recently been receiving.
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Apr 13 - Another feeding episode.
Lately, we've only been noticing three young; either the youngest two
are still visually imperceptible amongst all that fluff, or they've
since died and been eaten by their nestmates. It is worth pointing out
that the nest mortality of first year Barn Owls is often quite high.
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Apr 12 - The male and female spend all
night getting food for the chicks. In fact, the male seldom enters the
box anymore; he just sticks his catch through the nest box hole and
leaves.
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Apr 11 - As with last year, we are awarded good views periodically of the spider sharing this nest box with the chicks.
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Apr 10 - This is the first shot of the
eldest chick venturing away from his/her nestmates. At this stage, the
eldest chick is putting on about 11.5 grams of weight each day!
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Apr 9 - Careful observation of this
shot will reveal four out of five young; perhaps from the physical
development of each bird you can tell which hatched first and which
hatched last?
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Apr 8 - The female tends to the young.
Lately, both she and the male have spent most of the night searching
for food, leaving the young unattended.
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Apr 7 - The young in their corner. Notice how clean the nest box looks - the female eats the nestlings' feces.
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Apr 6 - With wing stretched out, the
female broods her chicks. Shortly, however, the eldest chicks will be
too large to brood, at which point the female will stop brooding
altogether, leaving the smaller chicks to be kept warm by their
siblings.
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Apr 5 - The eldest chick begs for
food. This shot highlights the reptilian ancestry of birds - at first
glance it almost looks like a tiny tyrannosaur has invaded the nest!
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Apr 4 - The young huddle in their
corner, the eldest chicks starting to show greater body definition
amidst all that fluff. Interestingly, the young will probably continue
to roost with each other well after leaving the nest.
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Apr 3 - From here on out, the chicks will be so demanding for food that both male and female will have to go hunting at night.
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Apr 2 - As the chicks mature, the male starts to assist in feeding them.
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Apr 1 - The female feeds the chicks, extending a gentle wing around them to keep them warm.
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Mar 31 - Amazingly, yet another copulation event atop the chicks.
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Mar 30 - The huddled mass of fluff is actually five young Barn Owls ranging in ages from 1 to 11 days.
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Mar 29 - A viewer from San Francisco sent us this image of the female and her young shortly after the last egg hatched!
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Mar 28 - The eldest chick has already doubled in size and is starting to crawl about.
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Mar 27 - The adult Barn Owls continue to copulate, even on top of the hatchlings.
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Mar 26 - Two important terms used to describe young Barn Owls are altricial, meaning that they hatch naked with eyes closed, and nidicolous, meaning that they stay in the nest.
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Mar 25 - At this stage, the male
continues to capture the food, but only the female feeds the young. She
does so by tearing the meal into very small bits.
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Mar 24 - The third chick made its appearance today!
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Mar 23 - The tiny chicks will grow
quickly now--they actually overshoot their adult body mass by the time
they are 30 days old, then return to normal before they fledge.
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Mar 22 - The second chick hatched today! Here is a great picture of the two owlets.
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Mar 21 - The little owlet can only
crawl now, but will be able to strongly lift its head when it's about
12 days old and walk at around 14 days.
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Mar 20 - The male and female huddle
together over their chick. The female will continue brooding
until the first owlet is about 25 days old.
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Mar 19 - With the male and female briefly away from the nest, we can make out a small fuzzy mass. The first owlet has arrived!
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Mar 19 - The female sits tight atop the eggs, but some time around 8 PM, we see the first sign of egg hatching—shell fragments!
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Mar 18 - This encounter between the male and female allows a view of the entire clutch of five eggs.
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Mar 17 - Another quiet day in the nest
box. Although Barn Owls prefer to roost in cavities, they will often
roost in leafy trees in the summer.
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Mar 16 - Was it this owl pair that
used the nest box last year? Despite not having the bands to prove it,
these owls are probably the same ones since Barn Owls have very high
nest site fidelity.
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Mar 15 - A viewer from Concord, CA
sent in this spectacular image from the side cam. It's certainly the
biggest rodent that we've seen the owls bring into the nest box so far!
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Mar 14 - In this scene of domestic
tranquility, the male strokes the incubating female. Things should
remain serene until the eggs hatch!
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Mar 13 - Occasionally the female will
leave her clutch completely unattended at night, though usually only
for a couple of minutes.
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Mar 11 - In this side shot, the
preening male's "round head" and ridge of facial feathers can be seen.
Barn Owls are distinct enough from other N American owls to be placed
in their own family, Tytidae.
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Mar 10 - The female vocalizes to the
male outside the box. The Barn Owl's call is very aptly described as a
"bloodcurdling shriek," especially when they are disturbed.
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Mar 9 - The female tenderly rotates
her eggs. When the young are about ready to hatch, they will vocalize,
whereupon the female will respond with soft calls.
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Mar 8 - It's been a quiet couple of days for the owl pair. The male seems to be curious about the camera.
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Mar 7 - Copulation at this point serves primarily to reaffirm pair bonds.
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Mar 6 - The female switches positions,
allowing a peek at her five eggs. It takes about 30 days for a Barn Owl
egg to hatch; therefore, the first egg, laid Feb 16, should hatch
around Mar 18, whereas the last egg, laid Feb 25/26, should hatch
around Mar 27.
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Mar 5 - A hungry female wolfs down a
mouse. Within about 6.5 hours of this meal, she will regurgitate the
mouse's fur and bones in a compact wad known as a pellet. It is thought
that pellet regurgitation is stimulated by the next potential meal.
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Mar 4 - The female preens the male while he rests.
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Mar 2 - The owls are still mating,
though the clutch is now complete at five eggs. You can see that
the male brought a meal home for the female--she is holding it in her
beak.
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Feb 28 - It's been nearly three days
since the fifth egg was laid, so this is probably the entire
clutch. Barn owls can have clutches of up to 13 eggs, though the
average is around 7.
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Feb 27 - The male passes time by
picking at some leftovers on the floor. The soft 'bedding' in the
box is mostly crushed owl pellets.
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Feb 26 - The pair will continue to mate with decreasing frequency throughout incubation and chick rearing.
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Feb 25 - The female is rotating the eggs again. There are four now!
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Feb 24 - Thus far in the egg laying period, the owls
have been copulating at least four times daily, though the frequency
has diminished since egg laying began.
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Feb 23 - In this late afternoon shot, the male awaits
nightfall, while the female rotates her clutch. Perhaps the male awaits
another egg as well?
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Feb 22 - It's been a successful
hunting night for the male. The barn owls' ability to find food
by sound is the most accurate of any animal tested!
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Feb 21 - The third egg has appeared! We should be seeing a new egg every two or three days for the next two weeks.
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Feb 20 - The female rotates the eggs
often, using her beak or feet. Frequent rotation keeps the
embryos suspended in the center of the egg, ensuring proper development. |
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Feb 19 - Another egg! The female
will continue laying and incubating for the next couple of weeks,
creating a large age difference between the youngest and oldest
chicks.
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Feb 18 - The egg was left alone at
least three times today. The male barn owl continues to feed the
female during incubation, so she rarely needs to leave the nest.
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Feb 16 - This is one of the earliest
images we have of the first egg from this pair! The female has been
sitting tight since laying it, and we're eager to see how many more
she'll lay.
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Feb 14 - The female stretches out her
wing, showing the beautiful black markings seen on both sexes.
Barn Owls can have wingspans up to 45 inches, though hers looks extra
long from this angle.
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Feb 13 - The male has been providing the female with a steady supply of large prey items.
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Feb 7 - Both sexes solicit copulation
by crouching in front of the other. This is one example of that
behavior from many instances over the last couple of days.
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Feb 2 - Last night looked to be a more active one than usual for the owl pair; the camera archived three copulation events.
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Jan 19 - This pair continues to mate daily, though it could be a while before we see their first egg.
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Jan 14 - This photo offers a great
view of the facial disk. Note that the brown outline around the face is
seen better in the daylight than at the time this photo was archived.
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Jan 10 - According to records from our
California cam host, it appears that the owls have begun mating at
least a few weeks earlier than last year.
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Jan 7 - Today was a particularly active day for the owls—our cameras captured six copulation events!
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Jan. 4 - Since January 1st, the owls have been mating on a regular daily basis.
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Jan. 1, 2006 - The time spent over the past few months roosting
with and preening one another has created a strong pair bond for the
upcoming nesting season.
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