My runs around Davis lately have been peppered by high-pitched, double-syllabic calls emerging from treetops and house roofs. They come from black phoebes, handsome little flycatchers that are keeping an eye on their suburban territories.

If you're a gardener or farmer- these little guys should be on your radar. They are insectivores: ravenous consumers of pest insects galore. On the wing, they are  acrobatic hunters- taking out flying insects and gleaning from leaves and plants.

According to the National Audubon Society, the phoebes (a group of tyrant flycatchers including the Eastern-, Black-, and Say's- Phoebes) are named for their call: which sounds like they are repeatedly saying 'Phee-bee'. I wonder though, if their name comes in part from the Greek Titan Phoebe; who was associated with the moon and was grandmother of the great hunter Artemis. The grey, black and white color palette and hunting prowess of these elegant tyrants certainly seems to match the vibe of those Greek super-powers. 

There are 3 species of phoebe in the US- the black phoebe, the Say's phoebe, and the eastern phoebe:

Phoebes are sit and wait predators: they hunt from a perch and visually sight their prey before pursuing and capturing it. They can often be spotted perching on a good vantage point- bobbing their tails and sometimes expressively lifting their small black crests. They are hungry birds too. One study from California in 1985 found that black phoebes caught an average of 1.21 prey items per minute over the course of a day. If that rate is consistent, one black phoebe can eat 73 prey items per hour; over a ten-hour hunting period that is 726 prey items per day; and over a year that adds up to 264,990 prey items (!). Black phoebe's primarily consume small wasps, spiders, flies, moths, butterflies and grasshoppers. They have even been known to fish small minnows from shallow water. Say's and eastern phoebes have similar diets.

Black- and eastern- phoebes traditionally build their nests from mud on sheer-sided cliffs near sources of water.  Say's phoebes rely less on mud as a substrate- possibly because of their wider range and lesser association with waterways. All 3 species like to have a roof over their heads while nesting. The eaves of houses and spaces under porches and in garages have become new favorite nesting sites for the birds in towns within their range- and have even been attributed to widening the area in which phoebes breed. YouTube is full of home-shot vidoes of phoebes feeding their young- and even a few that have learned to take food from their host (human) family.

Eastern phoebe nests can sometimes harbor unwelcome guests. Brown-headed cowbirds, a bird that specializes in laying its eggs in the nests of other birds (a phenomenon known as 'brood-parasitism'), often call eastern phoebe nests their home. Cowbirds lay their eggs in amongst phoebe eggs, and pass along all their maternal duties to the unsuspecting phoebe parents. Cowbird chicks grow faster than their natural nest-mates by out-begging the phoebe chicks. This can result in very low nesting success rates in phoebes. In some well-studied eastern phoebe populations, only about 10% of parasitized nests fledge both phoebe and cowbird chicks- and in some areas up to 20% of nests can be parasitized. Habitat fragmentation has been linked with the spread of cowbirds around the country, and this has in turn been linked with increased parasitism in phoebe and other host bird nests.

Mark Hauber, a Professor in the Department of Psychology at Hunter University, studies the mechanisms of brood parasitism in birds around the world: including the co-evolutionary arms-race between eastern phoebes and brown-headed cowbirds. While many brood parasites actively try to kill or remove the natural eggs of their host parents from the nest, it may not be the best idea for cowbirds in phoebe nests. Dr. Hauber's work with colleagues has shown that cowbird chicks actually have the best growth rates when they allow phoebe chicks to remain with them in the nest. This is because the parent phoebes deliver more food to accommodate for their larger brood: food which the more aggressive cowbird can snag first.

[Side Note: As part of my PhD research, I found that New Zealand falcons brought more food to larger broods, but the chicks that had siblings got less food overall than single falcon chicks.]

Farm Rating: Friends year-round.
If you want to encourage more phoebe's around your property (and everyone should!), keeping waterways flowing and surrounded by natural vegetation is key. Count yourself lucky if you spot a cup-nest made from mud and mosses in the corner of your garage or under an eave at your house- a phoebe nest will give you hours of entertainment as you watch the parents tend to their 2 broods each summer (but be sure to keep your distance), and just think of the pest control services that one pair of Phoebes will give you over the course of a year!

More Reading:
Wolf, Blair O. 1997. Black Phoebe (Sayornis nigricans), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/268

All About Birds for Black Phoebe, Say's Phoebe, and Eastern Phoebe

The website of the Hauber Lab

Croston, R. & Hauber, M. E. (2012) The Ecology of Avian Brood Parasitism. Nature Education Knowledge 3(10):56

This Sunday is Superb Owl Sunday: A day when Americans and owl fans the world over sit down with some fantastic cheese-covered foodstuffs and partake in observing the glory, the superb creature, that is the OWL.

Thanks to Stephen Colbert's wariness of copyright infringement and what appears to be some genuine misspellings of the words 'super bowl' on twitter, the birding world is atweet with witty memes and photos of owls in all of their superb-ness.

Why should owls be receiving any attention in a week when professional athletes will be paid millions, nay, billions, of dollars to run across a field? Here's my shortlist of why owls are amazing and deserve to share the spotlight:

1. Owls can fly- SILENTLY.
As the stealthiest hunters out there- owls can fly without making a sound. Well, they do make a small amount of noise, but the wind that you'd normally hear whooshing around the wing of a falcon is nearly inaudible. This is because of comb-like serration on the leading edge of their wing feathers, combined with a soft back edge that muffles any sound. Owls also have extra down around their flight feathers and on their bodies, both for sound absorption and keeping warm- also, see point 5.

2. They can (almost) turn their heads around.
Famous fact known by most school children. Owls can turn their heads 270-degrees- all the better for surveying and listening to their surroundings (point 4) while waiting on a perch for prey to reveal itself.

3. Owls eat a ton of rodents.
Owls are birds of prey, and, depending on the species, their diets can include mammals, birds, lizards, insects and even fish. From my perspective as someone studying the pest-control services from birds for farmers, the rodent-gobbling habits of species such as the barn owl are incredible. Farmers here in California are flocking to encourage barn owls into their fields, since a single barn owl eats a minimum of one rodent per night. Using conservative estimates from data collected at a single California vineyard where owl boxes had boosted the population of owls to 102 individuals, Mark Browning and a team of scientists worked out that over 24,000 rodents were consumed by hungry owls over two years. That's 24,000 rodents in ONE vineyard. We have been talking to farmers near Davis about carrying out similar studies here to measure the economic benefits that they receive from barn owls.

 

4. Owls hear with their faces.
Owls' flat faces and specialized feathers form a facial disc that directs sound to their ears. As the video below says, their face is basically a giant ear. Hunting at night, owls can see much better in the dark than we can, but it's their exceptional hearing that often clues them in to their next meal. Owls can hear so well that they can pick out a nibbling rodent under a few inches of snow (see the excellent photo above by Kay Schlumpf).

5. Owls are fluffy and cute.
Ridiculously so. As we've already discovered, owls are loaded with extra down, making them fluffier than most birds of prey. Their large, forward facing eyes and round facial discs give them the features that humans find adorable. They also have wonderful personalities. Case in point: here is a photo of a baby owl named speckles. He was rescued by my colleague in New Zealand, Diana, who is the local bird rehab guru in the town I used to live in. Now, Specks was found in the middle of a paddock as an owlet (probably dragged out of his nest by a house cat that then got bored and left him). He was so small that he wasn't able to keep warm, and had no feathers. As an introduced species in New Zealand, Little Owls' aren't protected, so Diana raised him by hand at home. He's imprinted on humans, which is not normally something you'd want to do to a rescued owl, but in his case- he's being primed for stardom. Specks will be used for education in local schools to teach kids about owls- and hopefully to get them more interested in their native owl, the Morepork. For me though, I got the chance to hang out with this adorable, friendly, baby owl when he was just starting to take his first flights. He liked the back of his head to be scratched, preferred sitting on my shoulder or head (but was still quite happy perched on one pinky), and he didn't like the family dog. Sitting around the table, he settled down in my lap one night and then neatly tucked himself in by pulling the bottom of my sweater over himself. Awwwwwwwwwww.

This video may have the best opening statements of all times:
"Baby owls are called owlets and they look like a cotton ball that grew a face... and legs.
Owlets are born without flight feathers and because they are vulnerable they camouflage themselves... as muppets."

I see some pretty wonderful halftime ad opportunities featuring owls.

Christmas music has been bombarding us everywhere for the past month and we're all tired of it. Thankfully, today is boxing day- which means no more Christmas tunes for about ten months... but also that I'm a day late with this post.

At a party yesterday listening to the omnipresent 12 days of Christmas while drinking hot toddies (partially responsible for the tardiness of this post), I realized that the bird-laden song is devoid of North American species. This makes sense because it's an English song, but for new birders like me, I wondered about which of the species are likely to actually be part of our American 12 days.

Partridge have been introduced to the Americas (although we do have pear trees), turtle-doves are not found here, and French Hens are a specialized breed of domestic poultry, so they don't count.
We do have swans that a-swim and geese that a-lay, and because those laying geese are most likely the domesticated breeds that grace some Christmas tables, let's talk about our own wild swans.

In New York, where I grew up, we had mute swans in the estuary behind our house. As kids, we used to feed one of the resident pairs from the dock and always named them Pinocchio and Penelope, despite the fact that sometimes there were 6 pairs of Pinocchios and Penelopes. They had adorable cygnets but were nasty and terrifying and kept us off of the beach.  Beautiful as they are, these large, introduced Eurasian waterbirds can slurp up a lot of vegetation and out-compete smaller waterfowl, making them a conservation concern for many native species. In places like New Zealand (where they are also introduced) mute swans are considered the property of the queen. But in the Americas flocks are starting to get so large that they need to be controlled. The flock in our little estuary now numbers in the hundreds every year.

So, that leaves us with the trumpeter swan and the tundra swan. Both of these are cold-weather birds, and are not common in most of the lower 48. Trumpeter swans only grace Canada's plains, Alaska and part of the Prairie Pothole and Great Lakes regions. Tundra swans breed in the arctic circle and migrate to spend their winters along estuaries on the Pacific coast, parts of the Mid-Atlantic seaboard, a little of the great lakes and in some of Utah. If we were going to spot seven swans a-swimming in either my childhood home of New York, or my current home in the Central Valley- they'd probably be tundra swans.

Tundra swans are monogamous species that grace our wetlands and farmlands in the winter. Chicks stick with their parents until the next year's breeding season, so family groups and flocks may be spotted. Traditionally spending their winters on wetlands, tundra swans are now forced to over-winter on open fields in some areas where wetlands have been drained: sometimes leading to conflict with farmers. In places like the central valley though, initiatives like the Migratory Bird Conservation Partnership between Audubon California, The Nature Conservancy, and Point Blue Conservation Science, are providing the science, funding and logistics to target flooding of rice and arable fields in the winter so that waterbirds and waders have the habitat that they need to survive. In many cases, flooding fields instead of burning them can lead to lower pest pressure, better breakdown of stubble, and habitat for native fish species. A California-based study by Bird, Pettygrove & Eadie from 2000 showed that foraging waterfowl could increase the breakdown of rice straw by 78% compared to areas that waterfowl did not forage in: meaning that in some cases, waterfowl could replace autumn tilling in the mechanical breakdown of straw. These types of win-win situations where conservation and farming can be mutually-beneficial are some of the most exciting studies, in my view.

Trumpeter swans are the largest waterbird in North America and can weigh up to 12 kilograms (about 27 pounds). Because of this large size and their long milky-white feathers (which were used for making superior pen quills), the species was hunted almost to extinction by the early 1900s. Conservation efforts have helped the birds bounce back, but they are still threatened by competition from the mute swan, loss of their wetland habitat, and lead poisoning.

Trumpeters are monogamous species and mate for life after establishing a bond in their first 2-4 years. Birds can live to be over 20 years old, and have one clutch of 1-9 eggs per year. Eggs are large, roughly the weight of 6 large chicken eggs, and take over a month to incubate. Hatching takes 12 hours and is exhausting for the chicks. Because nests are built on the ground they are open to predation, so chicks need to recover quickly to leave the nest and head out onto the water within 1-2 days. These big birds take a long time to grow and develop their feathers and flight abilities- with most chicks fledging after spending over 100 days with their parents. 

I've never seen a trumpeter swan, but do remember reading The Trumpet of the Swan by Charlotte's Web author E.B. White. This story of a young boy who helps a swan who can't trumpet learn to write and play a brass trumpet, was one of my favorites growing up and would be a great festive gift for young readers next year. For me, I'd love the opportunity to see and hear a trumpeter swan in real life. Perhaps even seven-a-swimming.

Here is a video about 'Ultimate Animal Dads' that may stretch the analogies a bit.
'He's a big-daddy, a handyman, a good cook, and a stud rolled into one'
HA!

Read more: Mitchell, Carl D. 1994. Trumpeter Swan (Cygnus buccinator). In The Birds of North America, No. 105 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.

This week, the burrowing owl won a hard-fought battle to become Audubon California's bird of the year.

I want to declare my own winner for a slightly different competition- Grumpy bird of the year (which the burrowing owl might have had a shot at winning). That's right, the horned lark is the world's grumpiest-looking bird.

I'm sure that this statement will get me into hot water amongst birders and will bring out comments about owls, swallows, boat-billed herons, and pretty much any passerine nestling. But, with his black lores and cheek patches forming a cartoonish frowny-face, and what appears to be an 18th-century handlebar mustache on his head, the male horned lark above is about as grumpy-looking as a bird can be. If anything, the horned lark has a pretty habitual 'Not- Impressed' look on his face. Possibly not to the point that it can compete with the grumpy cat, but, for a bird, these guys are pretty surly looking.

I can't help but giggle every time I look at these pictures!

Farmers, gardeners and arachnophobes alike should delight in seeing flocks of bushtits flitting around their trees and hedgerows. These tiny birds are primarily insectivorous: eating large numbers of minute insects which they glean off of leaves and other foliage. Flocks of up to 40 birds move quickly through branches, constantly eating a diet that includes a number of crop pests: scale insects, caterpillars, beetles, moth larvae and ants.

Bushtits need to eat 80% of their body weight each day to keep up with their speedy metabolisms when weather is warm- they eat even more when it cools down. According to a study from 1907, bushtits in California had diets that consisted of 81% insect matter through most of the year, and which increased to 100% insect matter in the spring. This means that one bushtit eats over 3 pounds of insect matter every year- which is the equivalent of eating 908,000 ants! Have a flock of 40 birds frequenting your farm? They'll eat over 120 pounds of insect matter in a year!

Bushtits may also be the cutest birds out there- Their social mannerisms and tendency to seek warmth from their friends mean that they like to snuggle. Plus, they are tiny and fluffy.

Weighing in at just under the weight of a newly minted quarter (5.5g), bushtits have a hard time staying warm when temperatures drop. During the breeding season, families sleep together in their warm, fuzzy, hanging nests which are made from lichen, moss, fur, feathers, leaves and spiders webs (which provide a good amount of stretchy resilience). Even their home construction techniques are cute. Nests are built by creating a 'platform' out of spider webs in which one of the adult birds will sit to stretch it into a bowl shape- the pair will continue adding spider webs and other materials until the pendulum nest is large enough to accommodate their new family. A pair of bushtits work for an average of one month to build their nest.

Females will lay 1-2 clutches of eggs each year, with an average of 6 eggs in each clutch. At some nests, 'helper' birds will join the original breeding pair. These helpers are often adult birds who either do not have mates of their own or who have lost their nest. Because nest-building takes so long, birds that lose their nest after egg-laying sometimes do not build a new nest- and instead either try to steal a neighbors nest, or to join a neighbors nest. If the established pair will let helpers in, the new birds get a warm place to cozy up and sleep. Helper females may get the chance to lay eggs in the second clutch, and helper males may get to fertilize eggs in the first or second clutch (if he can keep ahead of the established male). The established pair, in turn, gets help with feeding and caring for their chicks.

Fortunately, bushtits are a relatively common species in California and are not of conservation concern at present. Because bushtits prefer to feed and nest in trees, retaining and replanting riparian areas, hedgerows, and trees around buildings will help increase their abundance on your property. Bushtits generally move as they eat, so they are less likely to fly across large open expanses to reach trees. They will venture through orchards and into fields from nearby trees.

Farm Rating: Friends year-round.

The video below shows a pair of bushtits working on their nest. Note that females have white eyes and males have brown eyes.

Further reading:
Sloane, Sarah A. 2001. Bushtit (Psaltriparus minimus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/598

Ah-monds

California is home to virtually all of the world's Almond producers (California produces at least 80% of the almonds on the planet- last year that was 2.1 billion tons). As it turns out, most of us say Almond wrong. Here, they aren't Almonds, they's Amonds. Why? Well, as the local saying goes- to harvest almonds, you need to "shake the L out of them!"

Watch this video and see just how much of a shake these tiny trees get each Autumn (note the appropriate music choice- 'shake it, shake it, Cali')

Last week, at a pollination workshop hosted by the UC Agricultural Extension office in Woodland, California, I learned a lot about both honey bees and native pollinators of crops in the Central Valley.

Almonds rely on insects for 100% of their pollination requirements, and pollination is the first and most important step in the almond producing process. In mid-February, billions- yes billions!- of flowers open up on Almond trees around the Central Valley, each demanding at least one individual visit from a pollen-carrying bee. Pollination is a delicate and labor-intensive process- and for almonds, it is essential. In the early spring, almond orchards around the state turn a pinkish-white, and flower petals make orchards look like they've had a recent dusting of snow. Pollination of the world's largest crop of almonds requires a big workforce, so growers call in the big guns. Beekeepers from around the country migrate to California in mid-February to provide the workforce- over a million colonies of bees, adding up to billions of individuals- it's the largest assembly of honey bees in the world.  In February and March, California literally buzzes.

If you look at beautiful photos of almond orchards in bloom, the sheer number of flowers is mind-boggling. So, when I couldn't get an immediate answer from google for the number of flowers on an almond tree, I decided to investigate a bit further. The following is based on representative numbers from sources that I consider to be reliable, but probably not very exact (links through to the sources if you want to investigate), so, don't take these figures to be exact, just to give us an indication of the job bees are expected to do for almonds.  Average nut set on almond trees in California is around 7,300 nuts per tree. At around 124 trees per acre, that's 905,200 flowers that need to be pollinated per acre of orchard. In California there are 800,000 acres of almond orchards. Across California, that means 724,160,000,000 flowers (over seven hundred billion!) were successfully pollinated last year. This number doesn't include flowers that don't successfully develop into nuts, so is likely to be very conservative.

Bees are crucial, and they need to be looked after carefully. In 2009 Scientific American published these photos of a typical breakfast with and without the pollinating services of honey bees.

Seventy-five percent of crops rely on pollination from bees, and around the world this reliance upon honey bees in particular is being revealed as an Achilles heel for agriculture. 
Something is causing honey bees to die, at alarming rates. 

Eric Mussen, an apiculturalist at the University of California Cooperative Extension, says that a storm of dangerous elements may be to blame. Bacteria (such as American foul brood), Fungi (such as Nosema spp.), Viruses (there are 22 named RNA viruses that affect honey bees), and Parasites (such as varroa mite)- all can kill bees or cause them to become ill. Because of the social nature of the bee hive, bees living in a colony can pass these culprits along to other bees or larvae. Pesticides, even if they aren't directly sprayed on the bees, can be picked up by worker bees and can cause a decline in immune function- opening bees up to infections.

Sustainability comes in many shapes and forms, but it is often hinged upon not over-exploiting, or relying too heavily, upon a single resource. In the case of pollination, sustainability means having a diversity of pollinators around a farm- not just honey bees, but native bees as well. So, like all good businesses, the crops that rely on pollination will need to diversify to ensure their returns. This diversity comes from the roughly 4,000 species of native bee that can be found in North America. Research has shown that native bees provide a LOT of pollinating services, increase the work ethic of the honey bees, and can even do a better job of pollinating than their Apis counterparts- with native bee pollinated flowers producing larger fruit. 

In fact, if honey bees are unable to keep performing at their incredible rates, we will reply more on native bees to step in and provide the pollination services.  This means providing the native bees, which don't live in hives and cannot be easily moved around like honey bees, with homes and alternate food sources.  Like all animals, bees need to eat, and they need a place to call home. Areas of natural habitat and non-plowed land provide food sources for bees, to sustain them when crops aren't flowering, as well as places to build nests and lay eggs. In vast areas of intensive agriculture, where huge fields are only broken by weedy edges and irrigation ditches there is little space for native pollinators to feed and live, which means fewer workers when the crops need pollinating. 

As UC Davis Professor Neal Williams describes it- this is the 'irony of intensive agriculture and pollination'. 

The solution? Part of it is to plant field edges with hedgerows where bees can nest, and which provide food for both native and honey bees when crops aren't flowering. These hedgerows can also provide habitat for birds to nest, and for beneficial insects that prey upon pests. More on hedgerows and their impact on animals in future posts.

I'd like to introduce you to a new friend. He likes to sing in my backyard in his ridiculously raspy, thin, high-pitched voice. He is very loud for his size. He's a bit glamorous, and has a shiny pink cap and bib that he likes to show off in the light. He and his girlfriend flit about and spill their drinks on our floor, making it sticky.

He's an Anna's Hummingbird- a beautiful, tiny little guy- with attitude. Named after Princess Anna Massena, the dutchess of Rivoli, who was obviously a bit of a looker. Audubon wrote that she was a "... beautiful young woman, not more than twenty, extremely graceful and polite" (Audubon and his Journals I, 1897, p. 314: I got it from Palmer. 1928, The Condor Volume 30, pp. 261-307).

He is also the fastest animal on the planet! Flying at 385 body lengths per second, they reach speeds of around 50mph during their flying displays- reaching G-forces that humans could not endure.