Barn owls, new research

This videm from Britain is called Slow Motion Barn Owl Attack.

From the Journal of Evolutionary Biology:

Reciprocal preening and food sharing in colour polymorphic nestling barn owls


Barn owl (Tyto alba) siblings preen and offer food items to one another, behaviours that can be considered prosocial because they benefit a conspecific by relieving distress or need. In experimental broods, we analysed whether such behaviours were reciprocated, preferentially exchanged between specific phenotypes, performed to avoid harassment and food theft or signals of hierarchy status.

Three of the results are consistent with the hypothesis of direct reciprocity. First, food sharing was reciprocated in three-chick broods but not in pairs of siblings, i.e., when nestlings could choose a partner with whom to develop a reciprocating interaction. Second, a nestling was more likely to give a prey item to its sibling if the latter individual had preened the former.

Third, siblings matched their investment in preening each other. Manipulation of age hierarchy showed that food stealing was directed towards older siblings but was not performed to compensate for a low level of cooperation received. Social behaviours were related to melanin-based coloration, suggesting that animals may signal their propensity to interact socially. The most prosocial phenotype (darker reddish) was also the phenotype that stole more food, and the effect of coloration on prosocial behaviour depended upon rank and sex, suggesting that colour-related prosociality is state-dependent.

Snowy owl news from North America

This video shows a snowy owl on a roof.

From in the USA:

Snowy Owls moving south—winter is coming!

27 October 2015

Thanks to Harry Potter, Snowy Owl is one of the most well-known birds in the world, and also almost universally adored. Who can say no to a massive, charismatic, white owl? Over the past few winters, much of North America has been graced by these ghostly owls, especially during the winter of 2013-2014. In that season, thousands of Snowy Owls irrupted further south than normal, particularly in the eastern United States.

Snowies were seen as far south as Florida (!), and a single bird even made it to Bermuda (!!). In Newfoundland, people were seeing hundreds of owls in a single birding outing, like this checklist with 138 individuals, and 55 from one viewpoint. Wow! We’re already seeing signs of another Snowy Owl invasion this fall, with early reports of birds far exceeding what was seen by this time in 2013. Will the numbers continue to grow throughout the winter? Only time will tell.

As illustrated by some of the above statistics, the winter of 2013-2014 was a glorious one if you like great birds. It seemed to be so good for Snowies that something along those lines might not happen again in the foreseeable future. But looking at the sightings coming into eBird from the Upper Midwest this past month, it seems like there is a chance that we could see a similar pattern this coming winter.

It is important to state up front that this opportunity for birders often reflects a very stressful time for the owls. Although it can be difficult to discern the precise reason why any owl may be turning up further south than normal, this reason is usually not to the benefit of the owl. Common reasons for these southern “irruptions” can include shortages of food further north in core wintering areas, or an excess of young birds that are driven from the better northern wintering areas to sub-par locations further south. Please take care when you encounter any of these owls, and avoid the temptation to get a frame-filling photograph or better look at the risk of stressing the owl. This is not to say that all photographers or birders are stressing the birds they encounter, but care should be taken with these owls, as well as with all birds.

Now that we’re all on the same page for how to respect an owl when you find one, how do you find one!? It can be simpler than you think—these owls turn up anywhere. Over the past four weeks, more than 50 Snowy Owls have been reported between eastern Minnesota and the Upper Peninsula of Michigan. One was even seen in southern Ontario as early as September 13th! Reports from more than 30 locations across Wisconsin have included some very unexpected places. Some of these, complete with photos, include a car roof in a parking lot; someone’s back deck; on a roadside sign; another car roof—someone’s truck; and even on a bridge railing at 10:45pm! Some of the Snowies even seem to like to take a spin on the water. You just never know.

During many of these irruption years, Snowy Owls will turn up in places like those shown above—downtown rooftops are a frequent haunt. The main thing you’re looking for is something that reasonably mimics the tundra—an open space that is usually barren or grassy, and has a source of prey. The prey could range from small mammals to sea ducks, the latter being hunted on the open ocean under cover of darkness. Snowy Owls are pretty amazing birds!

Although the above map of sightings this year so far is interesting, how does it differ from 2013 (the mega year), and 2014 (a year that still featured quite a few)? 2013 and 2014 are shown below, and have almost no reports through the end of October. Please report any Snowies that you find to eBird, to help us understand the movements of this mysterious species.

Although we won’t know what this winter holds until it truly arrives—it sure could be exciting! Combining this with exceptional numbers of Northern Saw-whet Owls that have already been reported in the Upper Midwest, it could be a winter filled to the brim with silent, graceful owls.

Great horned owl news from the USA

This video from California in the USA is called From Hatching to Release: the story of an orphaned Great Horned Owl.

From the Cornell Lab of Ornithology in the USA:

Savannah Owls on the Horizon

Last year’s surprise season with a pair of Great Horned Owls in Savannah, Georgia, captured the imagination of hundreds of thousands of viewers worldwide. In their first year of nesting on cam they successfully fledged two owlets from an abandoned eagle nest near the top of a dying loblolly pine (watch highlights). No one knows whether the owls will return and nest this year, but our partners at Skidaway Audubon have reported seeing the adults courting and making alterations to the nest.

In hopeful anticipation of the owls’ nesting again, we have activated all of the camera equipment added and a second camera for a wide, fixed view of the nest from the west. The cams are streaming live, and it may still be a couple months before the owls begin nesting in earnest (last year’s pair laid their first egg on January 1). Tune in and you may be lucky enough to be greeted by hoots in the distance, or even a pair of wide eyes staring back at you! Watch cam.

Texel island’s barn owls, what do they eat?

This video from England is called Barn Owls Hunting.

This month, there was research at Ecomare museum on Texel island in the Netherlands about pellets of local barn owls.

In 2013 and 2014, owls of De Grie had eaten, according to the pellets: 63 greater white-toothed shrews, three field voles, five root voles, one bank vole, one wood mouse and last but not least one water shrew. Water shrews used to be the only shrew species on Texel (the only Dutch Wadden Sea island where this species lives), but are unfortunately getting rarer now.

There was also research about owls nesting near the Mokweg. The results there were: 176 greater white-toothed shrews, 61 root voles, 3 wood mice, 10 field voles, 1 brown rat and 2 water shrews.

From the USA: Though widespread, the striped owl is not well understood but it is a distinctive and beautiful owl. As more studies focus on this bird, additional details about its behavior and needs can be discovered, mysteries resolved and steps taken to ensure it is always abundant for birders to see: here.

Owls are beautiful and mysterious raptors that are favorites for birders and non-birders alike. Unfortunately, they also face many threats and almost one-quarter of the world’s owl species are considered officially endangered, threatened or vulnerable to severe population declines. On the plus side, there are many easy things birders can do to help owls and encourage their conservation: here.

Owls are amazing but often misunderstood birds, and there are many irrational superstitions about them. Learning these legends and myths can help birders better understand owls and appreciate their diversity and impact on society: here.

Fossil giant barn owl discovery in Cuba

This video says about itself:

Endless Owl Evolution

8 February 2009

Owls are among the most fabulous things alive. They have long held a symbolic and even spiritual place in our history, but from an evolutionary perspective, they are just plain awesome. Note how so many have a remarkable camouflage-the white snowy owl would starve it it was too easily seen in the winter and most are grey or bark-colored so they easily blend in to their surroundings. Here I show less than a quarter of the known surviving species of owls worldwide.

From BirdWatching Daily in the USA:

Introducing Craves’s Giant Barn Owl, a new species named after Julie Craves


A new species has been added to the roster of birds that once lived in the West Indies.

It’s an owl, and an impressive one, a relative of the Barn Owl alive today but much larger. Gone for thousands of years now, it is known only from fossils unearthed in Cuba.

The discoverer, ornithologist and paleornithologist William Suárez, and Storrs L. Olson, curator emeritus in the Division of Birds of the Smithsonian’s National Museum of Natural History, described the new species recently in the prestigious journal Zootaxa.

When they did, they bestowed on BirdWatching contributing editor Julie Craves an honor that few ornithologists ever live to see: They named the owl Tyto cravesae, or Craves’s Giant Barn Owl.

I interviewed Suárez and Craves about the owl, and the honor. My questions and their responses are below. — Chuck Hagner, Editor

What makes a barn owl a giant barn owl?

These extinct owls are called giant because they were much larger than living species of barn owls. In fact, at least one species was nearly twice the size of our familiar Barn Owl (Tyto alba). Their large size was the result of specialization in their mammalian prey.

Prior to the publication of Suárez and Olson’s paper, five giant barn owls from the West Indies had been described. In addition to describing Craves’s Giant Barn Owl as a new species, the paper reviewed the status of the other species, resulting in two of them being considered synonyms of others.

By the way, they shouldn’t be confused with extinct Cuban giant strigid owls, in the genera Ornimegalonyx and Bubo. (Ornimegalonyx, the Cuban Giant Owl, stood about three feet tall and is thought to be the largest owl that ever existed.)

What kind of bird was Craves’s Giant Barn Owl? How many years ago did it live? What did it eat?

Craves’s Giant Barn Owl was a nocturnal predator. It lived during the Quaternary, in the Pleistocene epoch (2.5 million to 11,700 years ago), but probably also into the Holocene, the epoch that followed and continues to the present.

Like all barn owls, it ate mostly mammals, especially rodents. While barn owls today most often eat mice and voles, the giant barn owls of the West Indies were specialists that ate larger rodents. Bones of prey found in fossil deposits formed by the predator indicate that hutias were the principal dish on the menu. Hutias are rodents endemic to the West Indies. They weigh from four to six pounds.

How was it related to the Barn Owl familiar to birders in the United States?

They are congeneric species, in same genus Tyto.

What does it tells us about Cuba (and the West Indies) in the Quaternary?

This fossil barn owl is another element in the West Indian avifauna that evolved to a gigantic form, resulting from the evolution on these islands where no predators on mammals existed, other than birds. The ecological role at the time completely relied on the raptorial avifauna, including large condors, eagles, strigid owls, and others.

What might have made it disappear? Could it have persisted into historical times?

For a highly specialized predator, it is very difficult to survive when your principal prey vanishes. This was the main cause of the disappearance of Craves’s Giant Barn Owl (and others). These barn owls probably persisted into the Holocene, after humans arrived on the islands.

William, where did you collect the fossils of Craves’s Giant Barn Owl?

I collected the material in June 1998 in a cave complex in Artemisa Province, Cuba, southwest of Havana. The bones were in a wall cavity about almost five feet (1.5 m) from the floor of the cave. This is also the type locality of several other fossil Cuban birds, including the Cuban Condor (Gymnogyps varonai) and one of the Ornimegalonyx owls.

Julie, how do you know William? You have described him as a “truly amazing person.” How so?

I met William over 12 years ago while assisting with a number of licensed bird-survey trips to Cuba. William participated as a guide and authority on Cuban birds through his position as curator at Cuba’s National Museum of Natural History. I liked him immediately — so smart, a great sense of humor, charming, and of course, a mutual interest in birds! Over the years, I grew to admire his dedication to science and West Indian bird studies. His perseverance and optimism no matter what obstacles he has faced have been sources of inspiration to me.

William, why did you name the owl after Julie?

For her dedication to avian conservation and her boundless appreciation of Cuban friends and birds.

Julie, why is having a species named after you a big deal?

Most people say it’s because it makes your name immortal. I’ve never been too concerned about my name living on, but my goal as an ecologist has always been to contribute to conservation in some way, however humble, that will make a difference in the future. William’s accomplishments far eclipse my own, so, for me, the fact that he respects my work enough to name a species after me is a true honor. That recognition means I must be doing something right, not to mention it affirms the close ties of our friendship. And yes, I will admit, the bragging rights are very cool.

Very cool, indeed. We couldn’t be happier for Julie. Please join me in congratulating, and bragging about, my dear friend on this profound honor. — C.H.

About Julie Craves

Julie is supervisor of avian research at the Rouge River Bird Observatory at the University of Michigan Dearborn and a research associate at the university’s Environmental Interpretive Center. Her column “Since You Asked” appears in every issue of BirdWatching. She has written for the magazine since June 1994.

Read Julie’s column ‘Since You Asked.’

Read her article about the birds of Cuba.

Read Julie’s article about coffee and birds.

Julie also writes regularly at Net Results, the blog of the Rouge River Bird Observatory; at Coffee & Conservation, her acclaimed blog about coffee and the environment; and at Urban Dragon Hunters, a blog about the distribution of dragonflies and damselflies and their role as bioindicators, especially in urban systems.

Helping owls nesting in the USA

This 6 August 2010 video from the USA says about itself:

Building a Screech Owl Nesting Box

From NestWatch eNewsletter in the USA, October 2015:

Owl About Birdhouses

Did you know that most owls do not build a nest or gather any nest-lining materials? (The notable exceptions are the Short-eared Owl and the Snowy Owl, which build ground nests.) Most North American owls depend upon a cavity in a dead tree or broken-off trunk if they are cavity-nesters, or they repurpose the old nests of other raptors if they are platform nesters. Sometimes, an old barn or duck blind will fill the need. Building a nest box or nest platform for your local owls is a fun fall project that will outlast any jack-o’-lantern. Right now, pairs are searching for suitable nest cavities in advance of the breeding season and calling to establish territories.

Eastern and Western screech-owls are commonly found in suburban neighborhoods with some tall trees, and in large cities with urban parks. Barred, Northern Saw-whet, and Boreal owls choose mature woodlands for their nesting sites, preferably near water. Barn Owls nest in open habitats, similar to bluebirds, and often choose agricultural areas. Great Horned and Great Gray owls will accept basket-style nesting platforms placed in the forest interior. Use our Right Bird, Right House tool to find out which owls nest in your region and habitat, plus tips for attracting them to your box or platform.

Shh—Day Sleepers!

Scientists still know very little about the breeding habits of owls, and their nocturnal ways make them difficult to study. You can help by installing a nest cam in your owl box and reporting your data to NestWatch. A nest cam helps you keep tabs on the owls without disturbing them during the day when they’re resting.

Conference on owls in the Netherlands

This video from Texas in the USA is called Great Horned Owl Hooting; Territorial Evening Call At Sunset.

On Saturday 10 October 2015, there will be a conference about owls, in Schouwburg Ogterop, Zuideinde 70 in Meppel town in Drenthe province in the Netherlands.

This conference will start at 9:30.

There will be lectures on about all owl species living in the Netherlands, including barn owls, little owls and eagle owls.

Romke Kleeftstra will speak about short-eared owls and common voles.

Bart Ebbinge will lecture about snowy owls in the Arctic.

Karla Bloem will tell about great horned owls in North America.

The complete program is here.