Owls in Rain - April 30, 2013

FREQUENTLY ASKED QUESTIONS:

Q: I cannot see any owls. Where are they?

A: Burrowing Owls are diurnal and nocturnal, meaning they are active during the day and night. However, they do spend quite a bit of time in their burrow. Mostly the male stands guard at the entrance and the female spends more time below. But sometimes they will both be in the burrow, especially when disturbed. Wait and watch or check back often and you'll be sure to see them!

Q: What is that yellow post in the foreground?

A: The yellow post is actually a T-shaped perch that the owls can use for increased elevation to survey their surroundings.

Q: What is the best time to see them?

A: Burrowing Owls are most active at dawn and dusk so mornings and late afternoons are the best time to view them. But they will appear at any time of the day so keep watching!

Q: Why is there a fence around the owls and why are they so close to the road?

A: The fence protects the owls from disturbance and their burrow is in an irrigation swale on the school property. They need to nest in areas above the flood level and the area closest to the road is most suitable for them. Sometimes you might see people walking past. The owls are accustomed to the presence of people.

Q: When do they breed?

A: Typically burrowing Owls breed in the winter from January to March but these owls have been known to breed throughout the year and raise multiple broods.

ABOUT BURROWING OWLS

Appearance:

Burrowing Owl Live CamThe burrowing owl is a pint-sized bird that lives in open, treeless areas. The burrowing owl spends most of its time on the ground, where its sandy brown plumage provides camouflage from potential predators. One of Florida's smallest owls, it averages nine inches in height with a wingspan of 21 inches. The burrowing owl lacks the ear tufts of the more familiar woodland owls. Bright yellow eyes and a white chin accent the face. Unusually long legs provide additional height for a better view from its typical ground-level perch.

Habitat:

The Florida burrowing owl occurs throughout the state although its distribution is considered local and spotty. The presence of burrowing owls is primarily dependent upon habitat. Humans have created new habitat for burrowing owls by clearing forests and draining wetlands. Burrowing owls inhabit open native prairies and cleared areas that offer short groundcover including pastures, agricultural fields, golf courses, airports, and vacant lots in residential areas. Historically, the burrowing owl occupied the prairies of central Florida. Recently, these populations have decreased because of disappearing habitat while populations in south Florida coastal areas have increased due to modification of habitat by humans.

Burrowing owls live as single breeding pairs or in loose colonies consisting of two or more families. Unlike most owls, burrowing owls are active during both day and night. During the day, they are usually seen standing erect at the mouth of the burrow or on a nearby post. When disturbed, the owl bobs in agitation and utters a chattering or clucking call. In flight, burrowing owls typically undulate as if they are flying an invisible obstacle course. They also can hover in midair, a technique effective for capturing food.

Burrowing owls use burrows year-round; for roosting during the winter and for raising young during the breeding season (Feb - July). Florida's owls typically dig their own burrows but will use gopher tortoise or armadillo burrows. Burrows extend 4 to 8 feet underground and are lined with materials such as grass clippings, feathers, paper, and manure.

Behavior:

Burrowing Owl babiesBurrowing owls mainly eat insects, especially grasshoppers and beetles. They can be of special benefit in urban settings since they also consume roaches and mole crickets. Other important foods are small lizards, frogs, snakes, birds, and rodents.

Eggs are primarily laid in March but nesting can occur from October through May. The female lays six to eight eggs over a one-week period. She will incubate the eggs for 21 to 28 days. At hatching, the young owls are covered with white downy feathers and have their eyes closed. They emerge from the burrow when they are 2 weeks old. At 4 weeks, they are learning to fly but cannot fly well until 6 weeks old. They remain with their parents until they are 12 weeks old.

The Florida burrowing owl is classified as a "species of special concern" by the Florida Fish and Wildlife Conservation Commission. This means burrows, owls, and their eggs are protected from harassment and/or disturbance by state law. Burrowing owls are also protected by the federal Migratory Bird Treaty Act.

 Credit: Florida Fish and Wildlife Conservation commission

Burrowing Owls History in Florida

Burrowing Owls in Broward County FloridaBroward County has one of the highest densities of Burrowing Owls in Florida and it also has a very high human population density.  Not surprisingly, these factors bring Burrowing Owls into close contact with humans across the county. The Florida sub-species of Burrowing Owl is now classified as a threatened species in Florida and it is one of the rarest sub-species of Burrowing Owls.  Loss of habitat due to development, disturbance at burrows and negative interactions with humans are some of the threats facing this charismatic species.

A staggering 55 Broward County Public schools have Burrowing Owls on their properties. Through various education initiatives and with help from Project Perch many of the schools now protect their owls by providing suitable habitat and burrows. The owls return the favor by providing the students and teachers with a rare glimpse into the natural history of these fascinating birds.

Burrowing Owls have been present at our school camera location since at least 1984.  For most of this time the school had 1 to 2 pairs of owls nesting on athletic fields. At one point they tried to burrow in the sand for the long jump pit. For a long time they were in an area between the classrooms.  The pair in this area did very well and over time they became year round residents that were known to produce more than one brood in a year.  During occasional cold weather they would perch on top of a light box under the overhang of one of the classroom buildings. A school expansion project was started that would use the space where the owls had burrowed and a permit to remove the burrow was applied for by the school district.

The teachers and students were very interested in relocating the owls to a safer place and began a project that would create new “artificial burrows” for the owls.  Artificial burrows take the permit mitigation process further by not just clearing the grass but actually digging a starter burrow for the owls and installing a 3 foot tunnel made out of modified 6” PVC pipe.  Within a week of being installed the owls were at one of the burrows! Since the artificial burrows have been installed owls have not nested on the athletic fields or anywhere else on school grounds except where the artificial burrows are located.  Since the installation of artificial burrows the colony has grown supporting up to 3 pairs of owls, all breeding at once!  The owls from the old burrow area near the classrooms continue to raise multiple broods and 2 other pairs have moved in.  The owls have dug a new natural burrow near one of the artificial burrows.  The colony has numbered 17 at one point and fledged as many as 9 owlets during the normal breeding season.

The owl couple on the live camera feed is the youngest breeding pair in the colony and are a little over a year old. Although you cannot see it they are using one of the artificial burrows.  They have recently lost the last of their juvenile fluff and it looks like they may be getting down to the serious business of raising a family!  Several weeks ago, this pair was seen mating and they have spent more time feeding and spending most of their time close to home.  The male seems to be nervously guarding the burrow like an expectant father. Is the female feeding heavily to lay eggs or are there owlets down there that they are already busy feeding?  Join us as we track their progress!

NO CLIPS AVAILABLE AT THIS TIME

Perch Project - Protecting Burrowing Owl in SE Florida
Burrow Visitors: Commensalism versus Mutualism
Friday, March 21, 2014

The Tiny Visitor

We called the small bird the tiny visitor.  We asked Ken Schneider to help us identify it and he sent back "Looks like a Palm Warbler.  Line over eye, long legs, constantly moves tail up and down."1 The bird was always flicking its tail and he had described it perfectly.  Ken even got a picture of the tiny bird the one day he photographed the owls.

We thought the bird must be snacking on bugs at the burrow, but it was so small, it looked like owl food to us.  So we asked Dr. Mealey why this small bird kept visiting the owl burrow.  Dr. Mealey confirmed exactly what we thought.  "They are omnivores, simply being opportunistic with bugs that are attracted to the remaining prey." 2 Dr. Mealey wrote "There's also a possibility of commensalism/mutualism in which the warblers pick off parasites from the owl benefiting one or both of them." 2 So off we went to find exact definitions and to try and categorize the relationships we were watching. 

Commensalism and Mutualism

Commensalism is a relationship between two species in which one species obtains food or a different benefit from the other without either harming or benefitting the latter.3  The word derives from "commensal"; from the prefix "com" which means together and "mensa" which means table or meal; it means to eat at the same table.4  In biology, the term was originally used to describe the eating of food waste by second animals, like the carcass eaters that follow hunting animals, but wait until they have finished their meal.We definitely saw the Tiny Visitor scavenging bugs from around the burrow but never when the owls were actively eating themselves.

We also never saw any direct interaction between the burrowing owls and the Palm warbler but before the hawk arrived on March 7, 2014 we could hear the tiny bird chirping loudly.  One of the primary avian predators of the Palm warbler is also the Cooper's hawk who specializes in small to medium sized birds.So the Burrowing owls and Palm warblers share a predator and their alarm calls can alert each other to danger.  So the owls benefit too.  Mutualism is a relationship between two species in which each species is benefitted, also known as symbiotic.6

The Squirrels

There had been other visitors to the owl burrow.  When the cam first went live, the squirrels were the first and most common visitors.  They would run along the fence line, hop down in front of the owls and stop and look.  Their visits were very fun.  Too big to be a prey item for the owl, the squirrels seemed to be just nosey neighbors, but squirrels also have to worry about hawks.    

In her thesis research in 2012, Lisa Ann Hendersen investigated whether ground squirrel calls reduced predation on nearby Western burrowing owls.7 Her research showed that 60% of the time the ground squirrels responded first to a predator whereas burrowing owls only responded first 30% of the time.7 The squirrels stand up, whistle, chatter, chip, make a tonic call, run towards and dive into their burrows.7 Living in close proximity to and having squirrels around makes a lot of sense for the owls.7 Both species benefit by being alerted more often to the same predators. 

Smaller Scavengers and Predators: Flies, Dragonflies, Grasshoppers, Lizards and Skinks

The parent owls were defecating in the area to increase the bugs available for their owlets.  Once the owlets were hatched, there was a lot of feeding going on and the amount of remains around the burrow dramatically increased.  There were carcasses strewn everywhere, bugs crawling around and the burrow was literally buzzing with flies.  We would say the burrow looked like a macabre scene from a horror movie.  There were several scavengers small, medium and large who came to feed.  One morning there were 4 flies on the perch and we also saw grasshoppers and dragonflies. 

When the owls had their first set of nestlings there was a lizard on the perch.  For two days we saw a Southeastern five lined skink hanging around the burrow and even going inside.  We thought the owls must not be home at the time, but later the owls were seen at the burrow on both days so they could have been home.  Father owl brought their nestlings a live lizard and a grasshopper to help them learn.  Smaller scavengers and predators came to the burrow to find food items for themselves and for the most part they benefit, except when there are owlets and then maybe they become the food items.       

The American Crow, Mottled Duck and Mockingbird

Then a medium sized scavenger, the American crow, showed up at the burrow.  Crows are omnivores and have a very diverse diet.7 They will eat almost anything including bugs, other birds, frogs, snakes, nestlings, mice and carrion also makes up a small percentage of their diet.7 The crow wanted a carcass that was very close to the burrow but the male owl was guarding the owlets inside the burrow and so he chased the crow away.  The crow tried again and the male owl chased him off again.  Then father owl went back into the burrow and left the carcass right where it was and the crow grabbed it and took off with it.  Some viewers wrote that the crow stole the owls' lunch, but the owl had plenty of time to take it back into the burrow if they still wanted it, but the owls were done with it and so the crow could have it.       

Crows are not bad neighbors to have because crows will mob a predator.  A mob is an assemblage of individuals around a potentially dangerous predator.9 Mobbing is an anti-predator behavior and mobbing calls are used to summon nearby individuals to join in.9  Mobbing has evolved independently in many species whose young are frequently preyed upon.9 Crows mob Cooper's, Sharp-shinned and Red-tailed hawks which are predators they share with the burrowing owls.  So the crows benefit from the food at the burrow and maybe the owls get some help detecting predators.      

Besides the ability to drive the predator away, mobbing draws attention to a predator, making stealth attacks impossible.  Mobbing plays a critical role in the identification of predators and inter-generational learning about predator identification.10  The reintroduction of species have failed because the population lacks the cultural knowledge of how to identify local predators.10  Scientists are exploring ways to train populations to identify and respond to predators before releasing them into the wild.10  Perhaps there is some inter-species learning about predator identification, where owlets can also learn from crows how to spot hawks. 

When feeding the first set of owlets, we saw the owls bring nestlings and ducklings back as prey items.  We also saw a mother Mottled duck parade her ducklings past the burrow.  The ducklings snacked on insects and rested while the owls were all down in the burrow.  We wondered if this mother duck was already missing a baby and why would she bring them to the burrow to snack, but she did.  We saw a mockingbird standing on the perch and fiercely displaying at the owls not long after one of the nestling prey items showed up.  Mockingbirds, like crows, also mob their predators.  Had they too lost a nestling to the owls and were the mockingbirds mobbing the owls?  Were these relationships just predator and prey?  Or did the ducklings also benefit from increased foraging at the burrow?  Did the owls also benefit from better predator detection because Mockingbirds mob hawks too?

The Vultures

Later, on the very same day the crow showed up, two kinds of vultures showed up at the burrow, the Turkey and Black vulture.  Fans were concerned for the owls, but they were safely down in the burrow and the vultures walked around picking up all sorts of remains.  The Turkey vulture rarely, if ever, kills prey, but instead follows the smell of recently deceased prey.8  It is followed by the Black vulture, who cannot detect the smell of prey on its own but is stronger and can tear apart carrion that the Turkey vulture cannot.8  Their relationship is often described as one of mutual dependence, but the Black vulture is larger and when in multiples can bully the food away from the scouts.8  There were only a few vultures at the burrow that day and they peacefully cleaned up the area and then left.  The vultures scavenging seemed to be one of the few examples of commensalism we saw; the vultures were eating carrion and the owls did not appear to benefit or be harmed. 

A Completely Different Kind of Commensalism: Butterflies and Bees

In the summer we documented two Peacock butterfly visits and there are always butterflies and skippers seen landing around the burrow.  Butterflies and other insects engage in mud-puddling, where they aggregate on wet soil, dung or carrion and obtain nutrients like salts and amino acids.11 For male butterflies it increases their reproductive success and they transfer the nutrients to the female during mating because the nutrients enhance the survival rate of the eggs.12 When the owls dig and reshape their burrow they take soil from underground and transfer it to the surface.  They also deposit carrion and dung around the burrow, everything a butterfly needs to puddle.  In an urban landscape that is mostly concrete, pavement and sod, places to puddle are hard to find.    

We also saw a lot of bees around the burrow and one day we even saw an owl moving out of their way.  Another time we were observing the owlets from a safe distance and noticed all of these Halictid green bees in the area when we realized they were nesting underground in very close to proximity to the natural burrow.  Had the owls tilled the area for bees and did that loosen up the soil and allow them to burrow into the ground?

Another Complex Relationship: Fire Ants

We spent a considerable amount of time this fall trying to protect the owls from nearby fire ant mounds (see BuOw Blog 10). Then the owlet laid down one day and Dr. Mealey taught us about "anting".2 Anting is a behavior where the owls literally lay down in the ants, which allows the formic acid from the ants to clean their feathers from parasites (see BuOw Blog 13).2 Anting may also strip the ants of their formic acid and make them edible.2 We did see the owlet eating some small bugs, which could have been ants.  So their relationship is not always commensalism but sometimes a parasitic relationship, where some of the ants are definitely harmed.  Every once in a while something goes terribly wrong for an owl and the ants get the upper hand; because the local wildlife care center has treated an immobilized juvenile that had sustained too many fire ant bites on its legs.  Burrowing owls and ants have a complex relationship indeed.      

The Burrowing Owl's Ecosystem

"The plants and animals that are found in a particular location are referred to as an ecosystem. These plants and animals depend on each other to survive. In a delicate balance, these life forms help to sustain one another in regular patterns."13 The cam teaches us not just about burrowing owls, but about the entire burrow ecosystem and there is a lot that goes on in and around the burrow.  When we first started watching the cam, we expected to see mostly owls, hoped for owlets and knew we would see some prey, but we've seen so many other players in the owls' community and learned so much more.

Sources:

1 Schneider, Dr. Ken.  2014.  Personal Communication.

2 Mealey, Dr. Brian.  2014.  Personal Communication.

3Encyclopedia Britannica, http://www.britannica.com/EBchecked/topic/127789/commensalism

Harper, Douglas. Online Entymology Dictionary. http://www.etymonline.com/index.php?term=commensalism

5University of Michigan Museum of Zoology Animal Diveristy Web, http://animaldiversity.ummz.umich.edu/accounts/Dendroica_palmarum/

Encyclopedia Britannica, http://www.britannica.com/EBchecked/topic/399884/mutualism

7Henderson, Lisa Anne. 2012. Burrowing Owl Predation in the South Bay; Do California Ground Squirrel Calls Reduce the Risk? San Jose State University Thesis Research,  http://www.scvas.org/pdf/BUOWConsortium/BUOWPredation_LisaHenderson.pdf

8The Cornell Lab of Ornithology, All About Birds Bird Guide, http://www.allaboutbirds.org/guide/

9Curio, E. 1978. The adaptive significance of avian mobbing. I. Teleonomic hypotheses and predictions. Zeitschrift fur Tierpsychologie 48:171-183.

10Griffin, Andrea S., Daniel T. Blumstein and Christopher S. Evans. October 2000. Training Captive Bred or Translocated Animals to Avoid Predators. Conservation Biology 14(5):1317–1326.  http://dx.doi.org/10.1046/j.1523-1739.2000.99326.x

11Boggs, CL & LA Jackson 1991. Mud puddling by butterflies is not a simple matter.  Ecological Entymology 16(1):123-127. doi:10.1111/j.13652311.1991.tb00199.x 

12Medley S.R. & Eisner, T. 1996. Sodium: a male nuptial gift to its offspring.  PNAS 93(2):809-813.

13Geography for Kids, Ecosystem. http://www.kidsgeo.com/geography-for-kids/0164-ecosystems.php

ARCHIVES

  • Black, Speckled and Brown Eyed Owls
    When I first started learning about burrowing owls, Dr. Mealey, our local burrowing owl expert, told me about dark eyed owls. He suggested that I go to Brian Piccolo Park and look for an adult owl with black eyes so I could see one first hand but when I went there I couldn’t find that owl.
  • Owlets and Nestling Development - The First 30 Days
    The owlets began arriving on February 5th and for the first time we saw babies begging for food and still with their natal down. For the first month we watched them learn how to bug and fly. As we watched them develop, we also got an in-depth lesson in "parallaxing" and "anting".
  • Nesting Behaviors for These Owls
    As we watched the owls begin nesting for the second time, we kept a list of all of the nesting behaviors that we learned to look for and recognize. We also documented some very strange owl droppings.
  • The Fire Ants Arrive
    Sunday September 22, the text came in, “Dirt in foreground. Ants? Too far from burrow for owls.” The grass was long and there was some extra dirt in the foreground, but on camera it was hard to see. It was even harder to tell that the extra dirt was ant mounds.
  • The Coop Arrives
    Later that week, the owls seemed nervous, checking skyward all the time. They would retreat into the burrow and stay there. We thought they were worried about an aerial predator, but on June 26 we would learn just how real their concern was.
  • Dispersal: Where do the owls go?
    Even before Tropical Storm Andrea, the burrowing owls had started to disappear. We were not at all surprised; they were always scarce in August. We knew the owls dispersed after nesting. We had been telling the students that owls dispersed once their young were fledged, because they could.
  • Burrowing Owl Colonies
    Burrowing owls are considered colonial nesters. In the 1890s, colonies of 200 to 300 Burrowing owls were described on the Kissimmee Prairie. Here are some of the first descriptions of the Florida burrowing owls published by the Smithsonian in the Bent Life Series:
  • Behaviors, Activity Patterns and Time Budgets of Burrowing Owls
    When we first started watching the owls in April, their behavior seemed “normal” to us and what we expected. By mid-May, we could not believe the amount of food the male was bringing back to the burrow.
  • Do the Owls Have Eggs or Owlets?
    This is the question we have been getting the most. So we’ll tell you everything we know.
  • Project Perch's Artificial Burrow Design
    The artificial burrow design that we use, comes from Dr. Mealey; he is locally known as the Burrowing owl expert as he consulted on the movie Hoot. He has been our technical consultant at Project Perch for years and generously donates 2 out of every 3 hours he works for the schools.
  • Tropical Storm Andrea and Flooding Burrows
    On June 7, a little after lunch the rain really started falling; it was the rain bands from Tropical Storm Andrea. Around 3pm, I was on the phone with one of our partners and we were watching together. It really looked miserable out there and it just didn’t stop.
  • Nest Decoration
    On May 20, 2013 there was a small dark pile of something to the right of the burrow entrance. We wanted to know if it was a pile of “dung”. We were all ready to write about “dung décor”.
  • How to Sex the Owls
    In the past, we have had to rely on the observations of whoever seemed to know the most about the owls at their location, which usually did not include which one was the male or female and was not based on a lot of observation time in the field.
  • School Yard Burrowing Owls
    A lot of people were viewing the burrowing owls for the first time today. This generated a lot of questions! Some of us have been lucky enough to watch them for a little while as we worked through some technical issues. So I’ll start with some of the basics about “School Yard Burrowing Owls”.

What You Can Do To Help

Burrowing Owl Live CamInstall T-perches near owl burrows. Perches provide burrowing owls with an elevated view of the nest area, and also make the burrows more visible to mowing machine operators. Many burrows collapse each year when mower tires pass near the burrow entrance. If you put up perches, be sure that you keep the grass and weeds trimmed low around the burrow to give the owls the unobstructed view that they need to avoid predators.

Restrict use of pesticides. Because burrowing owls feed on insects that are considered pests around homes, they are exposed to the insecticides you use. Pesticides decrease and possibly contaminate food available to owls. Explore options other than using pesticides, but if you continue to use them, please do so with caution.

Attracting owls to your lawn. Burrowing owls may dig burrows in sodded yards if vacant lots are scarce. To attract a pair, remove a 1-2 foot circular plug of sod from the lawn. This exposes the sandy soil needed by the owls for burrowing. You might also start the burrow and place a pile of loose sand near the mouth.

Placing a T-perch near the burrow can help draw it to a pair's attention.

Report malicious destruction or harassment of burrowing owls or their nests.
1-888-404-FWCC (3922).

Florida Fish and Wildlife Conservation Commission

Burrowing Owl Coloring Pages

Please click here and here for printable Burrowing Owl coloring-in pages.

Burrowing Owls: Superheroes of the Bird World and Our Environment
Learn about Burrowing Owls, their special adaptations and the role they play in our Florida environment with our interactive presentation.  After the children have seen the presentation, they can make paperplate owl masks and view the live feed.  Supplies needed for the craft are a paperplate and a tongue depressor for each student and tape and crayons.  The presentation should take about 10-15 minutes and the craft is about the same.  Click here for the presentation.


We will be developing this page as a useful resource for kids and teachers. Check back often for updates.

Welcome to our Burrowing Owl Wall of Fame!

Send your pics of the cam to info@birdingadventures.com and they may just end up on this Wall of Fame. You can take pictures of the cam using the Grab tool on your Mac or by taking a screen shot on your PC. Key moments and interesting behavior will be featured here!

The owls love the rain. Here they can be seen enjoying the respite from the Florida heat!
Owls in Rain - April 30, 2013
The owls love the rain. Here they can be seen enjoying the respite from the Florida heat!
Burrowing Owls feed mainly on insects but they will take lizards, rodents and even frogs.
Owl with frog - April 30, 2013
Burrowing Owls feed mainly on insects but they will take lizards, rodents and even frogs.
The owls love the rain. Here they can be seen enjoying the respite from the Florida heat!
Owls after the rain - April 30, 2013
The owls love the rain. Here they can be seen enjoying the respite from the Florida heat!
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