Category Archives: animals

A Bird that Teaches Itself to Sing: The White-crowned Sparrow

White-crowned sparrow ©Tim Jones
White-crowned sparrow (Zonotrichia leucophrys nuttalli) ©Tim Jones

I’ve just finished Richard Dawkins’s self-narrated audiobook of  An Appetite for Wonder: The Making of a Scientist, where, introducing a task given to him by his research supervisor Niko Tinbergen, related to nature versus nurture aspects of animal behaviour, he makes special mention of the White-crowned Sparrow (Zonotrichia leucophrys nuttalli).  As it happens, earlier this year I caught this native of North America pecking at a fig.

White-crowned sparrow ©Tim Jones
White-crowned sparrow (Zonotrichia leucophrys nuttalli) ©Tim Jones

Is behaviour built in at birth – innate and instinctive?  Or is it learned from experience?  One way ethologists, who study animal behaviour, try to answer such questions is to compare the behaviour of subjects artificially deprived of normal early life learning opportunities with those raised in their natural habitat.

Richard DawkinsIn the case of birdsong, tests on Sedge Warblers show they automatically know their song without ever hearing the tune from another bird.  As Dawkins puts it, they ‘fumble’ towards the final song, trying different sounds and sequences from which they assemble a correct version; so the process is innate: it’s all ‘nature’.

The White-crowned Sparrow also teaches itself to sing its unique song by fumbling and picking out the good bits, but, unlike the Sedge Warbler, it needs to have heard its song from another White-crowned sparrow in early life; it needs a prompt to know where it’s going – so to speak.  As for many animal behaviours, including human behaviours, the White-crowned Sparrow’s song is the product of a nature-nurture combo of innate and learned influences.  Dawkins wonders what similar early life deprivation experiments, within ethical bounds, might be made to study the human condition.

You can hear the White-crowned sparrows song here at the Cornell Lab of Ornithology.

A Sticky Moment with a California Tree Frog

Tree frogs in trees are just fine, but tree frogs on plate-glass windows are better – because then you get to see their slightly icky fascinating undersides.

Pseudacris cadaverina - California Treefrog ©Tim Jones
Pseudacris cadaverina – California Treefrog ©Tim Jones

 

I must admit, what struck me most when this guy landed – ‘thunk’ – out of a fig tree onto our window in Los Angeles, was how much his (her?) legs looked like raw chicken.  I’ve always shied away from those cuisses de grenouille opportunities, but I know the meat is often compared to chicken.  IMG_2517_280Why frogs and chickens developed that way is an interesting question, but not for today’s post.

Rather, now I’m back in the UK , where the frogs are less acrobatic, I’ve tried to figure out how our unexpected visitor managed to cling on.

 

Wet Adhesion

To understand that for the West Indian tree frog, Oseopilus septentrionalis, researchers Hanna and Barnes used active and anaesthetised frogs in experiments that measured the forces they apply walking up vertical surfaces, the angle at which they drop off a gradually inclined surface, and the shear force experienced by an individual toe when the surface it’s attached to is suddenly slid from under it.

The experiments involved placing frogs on a variety of strain-gauge instrumented platforms and surfaces, and making videos of frogs placed on runways and rotating discs of transparent perspex.

The researchers concluded that the primary mechanism tree frogs use to get a grip is exactly the  same as that which keeps a sheet of wet paper stuck to the side of a glass: wet adhesion.

IMG_2517_2_280rotWet adhesion combines a mix of viscous and surface tension forces, both of which require liquid and, in the case of surface tension, an air-liquid interface.  In the tree frog, that liquid takes the form of mucous – wait for it – pumped out the ends of its toes.

The mucous appears from perfectly smooth-looking toe pads that are actually covered in thousands of peg-like cells between which mucous flows from glands.  I can see something going on in my own photographs, but the structure is clear in the SEM picture below.

 

IMG_2516_2_280rot

Hanna and Barnes’s also looked at how tree frogs release themselves to move.  The frogs peeled rather than pulled their feet off surfaces, the peeling force engaging automatically in forward movement, but not in reverse or when the belly skin of the frog made contact with the surface.

 

Frogs placed on a slowly rotating vertical disc reorientated themselves to avoid facing downwards – presumably because of the involuntary forward travel or detachment that would induce.  At first sight then, my Pseudacris cadaverina appears to defy that rule – because he’s clearly inverted in one of the pictures; but that could be explained by the extra adhesion he’s getting from the inner thigh area – corresponding to the aforementioned belly skin.  What’s more, the authors point out that toe pads have developed independently several times in tree frogs, so the observed peeling mechanism may be peculiar to Oseopilus septentrionalis.

I would have liked to spend more time with this little guy, but after about ten minutes I looked up and he’d gone – probably back into the fig tree.  But for a while there he sure provided a level of interest, conversation, and intrigue way out of proportion to his size.  Ribbit.

climbersmall
Apparatus to measure climbing force

 

Tree frog toe pad. After Hanna & Barnes, 1991.
Tree frog toe pad. After Hanna & Barnes, 1991.

 

 

References

1. Adhesion and detachment of the toe pads of tree frogs. Gavin Hanna, W.John Barnes. Journal of Experimental Biology 155, 103-125 (1991)

Sticky End for a Carpenter Bee

Carpenter Bees look like Bumble Bees, but are black all over with an almost hairless abdomen.  A penchant for boring into wooden structures to make their homes makes them unpopular with owners of wooden homes – understandably.

Carpenter Bee Caught in Spider Web (Photo: Tim Jones)
Carpenter Bee Caught in Spider Web (Photo: Tim Jones)

I snapped this one, dead, hanging directly over the back door porch.  Which is a little worrying, seeing as the web it’s hanging from belongs to one of these guys:

Black Widow Spider (Photo: Tim Jones)
One I took earlier. Black Widow Spider (Photo: Tim Jones)

Recognizable by its bulbous abdomen and red hour-glass insignia, the Black Widow spider weaves a characteristically disheveled web.  This Western Black Widow, Latrodectus hesperus,  is the only kind found in California. (Reminder again that I’m visiting the US at the mo’; we don’t get these in the UK – thankfully.)

The popular myth that a Black Widow bite will, guaranteed, kill a person outright dead everytime seems a bit overblown (ref. University of California.).  But reports of painful muscle cramps, fever etc. suggest gloves are a good idea if you’re clearing out that dark corner of the garage; that’s where we found this guy.

See how in the top photo the web shines so nicely in the backlight?   That property, combined with the phenomenal strength of spider silk, wasn’t lost on the US military who, during World War II, harvested Black Widow spider silk for use as the cross-hairs of gun-sights (ref. Popular Science March 1944)

Here are some Carpenter Bees in happier times:

Carpenter Bee on the wing (Photo:Tim Jones)
Carpenter Bee on the wing (Photo:Tim Jones)
Carpenter Bee on the wing (Photo:Tim Jones)
Carpenter Bee on the wing (Photo:Tim Jones)

 

 

Hummingbirds and Wasps – not best of friends…

I’m still in California, and in the present heat-wave only good for staying indoors, reading stuff, and editing movie clips, like this one of the local hummers getting hot under the collar when an unwelcome, albeit suicidal, wasp pays a visit.

Wasps are aggressive and not above stinging a hummingbird (check out worldofhummingbirds.com) – hence the nervousness.

Incidentally, when I fished the wasp out, it wandered off a little crusty but still working.  We’ve had others pull the same stunt since though, and it’s quite amazing how long they survive, virtually fully submerged in hummingbird syrup; I’m talking 36 hours or so.  Presumably they have a tracheal breathing system like other insects, and can shut of their little breathing tubes if necessary; but this seems a long time to run on stored oxygen.  Are they taking it from the water/sugar solution?  Anyhow – something for another post.

 

Monkeying About In Space

With the news today that Iran has sent a monkey into space, it seems appropriate to post these pictures of the less than luxury accommodation occupied by chimpanzee Ham in an earlier era of space exploration.

Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)
Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)

I checked out the Mercury-Redstone 2 capsule on display at the California Science Center while waiting to view the Space Shuttle last week.

Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)
Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)

Four year old Ham, who was an ape rather than a monkey, launched into space on 31st January 1961.  He proved that beings similar to humans could survive and perform functions in space: to which end Ham was given a series of levers to pull on command (red, white, and black above).

Ham
Ham on his way (Photo:NASA)

It’s quite a mess in there:

Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)
Mercury-Redstone 2 Capsule (Photo: Tim Jones. Taken at California Science Center)

Amazingly, the capsule Alan Shepard piloted to orbit three months later didn’t look that much different.

Ham beats the Iranian monkey on altitude, reaching 157 miles against the Iranian’s 75 miles – not that either would be aware of how high they were.  The BBC report suggests the Iranian’s were testing the acceleration and deceleration of the rocket – although there’s the inevitiable ambiguity over why they’d want to do that, and the implications for weapons testing [monkey survives = warhead survives ?].

In related news, the U.S. National Institutes of Health announced this month they’d be stopping the use of chimpanzees for medical research; although I’m not sure where that leaves potential future space chimps.

 

Also of interest:

Guardian article on Ham http://www.theguardian.com/science/animal-magic/2013/dec/16/ham-chimpanzee-hero-or-victim?

Busy Bees

Bee and flower at Huntington Gardens © Tim Jones

Here are a few shots I took this afternoon of bees feeding on/pollinating one of the many species of Aloe that populate the Huntington Gardens.

Bee and Flower ©Tim Jones

The bees burrow and completely disappear inside the tubular orange flowers.

Bee and Flower ©Tim Jones

Bee with Flower © Tim Jones

Bee and Flower © Tim Jones

Going...
Going…
Bee and Flower © Tim Jones
Going…
Bee and Flower © Tim Jones
Gone (almost).

These two shots show the pollen baskets:

Pollen baskets are attached to the hind legs by a single hair
Pollen baskets are attached to the hind legs by a single hair
Bee entering Aloe flower with pollen baskets
Bee entering Aloe flower with pollen baskets
Aloe plant at Huntington Gardens © Tim Jones
Aloe Plant at Huntington Gardens (San Marino)
Humming Bird Feeding on Aloe (©Tim Jones)
These guys get a look-in too

 

 

Swans – Synchronised Preening

You may have seen swans performing various synchronised movements or ‘dances’ together on the water at mating time.

The pre-copulatory rituals extend to preening, and although we’re out of the breeding season, this local pair I snapped this afternoon are clearly keeping in practice.  Their synchronised stink-eye, reserved for loose dogs and over-eager photographers, is pretty impressive too.

Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)
Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)
Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)
Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)
Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)
Mute Swan Pair in Synchronised Preening (Photo:Tim Jones)

 

 

Orderly Animals

Gee, humans are smart.  Never mind the moon landing, today we have these fantastic slide-away pantries to squirrel our stuff away.  The ultimate in mall to wall storage efficiency.

Then again, maybe that honor should go to the first of two non-human tidy housekeepers that crossed my path this week: the Acorn Woodpecker (Melanenpes formicivorus):

I’ve written about woodpeckers before –  HERE.   But this example, snapped in Santa Barbara Zoo (of all places, given the birds are all over the area) is the best example of an acorn-saturated tree trunk I’ve seen.  Acorns placed by woodpeckers into holes excavated by woodpeckers – for later consumption.

 

Tidy Trashlines

Next up, the Trashline Orb Weaver spider (genus Cyclosa).  I came across this guy on a pick-your-own blueberry adventure at nearby Gaviota, strung across the bushes.  (And vulnerable to accidental picking –  it’s likely I ate one of these.):

Trashline Orb Weaver Spider
Blueberries
Trashline Orb Weaver Spider
Trashline Orb Weaver Spider

The spider is the darker lump at the center of the web, hidden among the string of five packages: its ‘trash’, made of bits of old victims, egg sacs, plant material and such like caught in the web.  I’d never seen one before, but now I now about them I’ve spotted a couple more in other locations.  Here’s one, startled to life below a vertical, albeit incipient, trashline:

Trashline Orb Weaver Spider

Left alone, they pull in their legs and try to look like a piece of trash:

Trashline Orb Weaver Spider
Trashline Orb Weaver Spider – legs tucked in

Incidentally, in the top picture you can see a visibly thicker, extra-strong, ‘cross-beam’ section of webbing, the stabilimetum, on which the main web and trashline hangs.

Why go to the trouble?   Spider researchers reckon the trashline disguises the spider from approaching food insects, which can then be grabbed more easily; but also hides it from predators ~ a strategy more effective against birds than wasps (ref 1).

Yeah, we’re smart – in some things; but we’re not the whole story by a long shot.

Of related interest

Decorative Spider Webs Attract Dinner‘ (BBC item from 20/9/12)

References and further reading

1. Detritus decorations of an Orb-Weaving spider (Cyclosa mulmelnensis): for food or camouflage ?  Tan E. & Li D., Journal of Experimental Biology, 2009, DOI 10.1242/jeb 030502 (pdf here)

2. Insectidentification.org

3. Trashiline Orb Weaver – A cool spider (abundantnature.com)

Photos copyright Tim Jones

Puzzling over Tyrannosaurs at the Natural History Museum of Los Angeles

Thomas and friends illustrate three stages of tyranosaur development (Photo:Tim Jones)
Thomas and friends illustrate three stages of development (Photo:Tim Jones)

How when we dig up a dinosaur bone do we know it comes from a young animal or a smaller example of a different species?  That’s a question the Museum of Natural History of Los Angeles collection of T.rex helps answer.

Los Angeles County Museum of Natural History ©Tim Jones
Los Angeles County Museum of Natural History

Yesterday, Erin and I visited the new Dinosaur Hall, where for the first time fossilised skeletons of three complete Tyrannosaurs are brought together to illustrate the different stages in the animal’s development.

 Thomas today: looking good
Thomas today: looking good

Above you see the three who died at 17 yrs, 14 yrs, and 2 yrs.

Here’s the largest, Thomas, as he looked a couple of years back when we last visited the museum: encrusted in rock, but the star all the same of his own very public extraction in the Dino Lab:

 in 2010 (Photo:Tim Jones)
Thomas being uncovered in the Dino Lab (Photo: Tim Jones)
Dino Lab in 2010 (Photo:Tim Jones)
In the Dino Lab visitors can watch the professionals at work

Dino Lab at Museum of Natural History Los Angeles

Dino Lab at Museum of Natural History Los AngelesComparing the three, we see that Tyrannosaurs don’t just scale up uniformly as they grow.  The eye sockets, for example, are more rounded in babies, changing to a keyhole shape in the adult.  The accompanying texts to the display explain how the relative length of the foot bone to the leg decreases from 70% to 50% from 2 to 17 yrs.

At 14 yrs. Adolescent, but dangerous.
2 yr old toddler Tyrannosaur

On a lighter note.  Ever wondered what a Tyrannosaurus rex looks like with (most of) its bones missing?  Probably not I guess, but here it is:

Boneless

This was a bit of fun we got roped into: a Tyrannosaur puzzle no less.   The bones of the T.rex are taken off the frame, and it’s up to us non-experts to put them back in the right place.   It’s harder than you might think – and it makes you think! (Shh – that’s the point).

Where to start…..

I got off to an easy start with those deceptively unimpressive fore-limbs we all know and love from Jurassic Park, but soon came to grief when it came to the ribs. Best leave things to the experts:

The tail bone’s connected to the …..er…..?

Assembling a Tyrannosaur is just like working on your car: there’s always an extra piece left over when you put it back together……

A tyrannosaur also guards the gate... (photo:Tim Jones)
A tyrannosaur also guards the gate…

Great exhibition and well recommended.   Thanks to NHMLA for an enjoyable afternoon.

 

Grease Ants

Grease Ants (Photo:Tim Jones)
Grease Ants (photo:Tim Jones)

Meet the Grease Ants (Solenopsis molesta).  Smallest ants I’ve ever seen. One or two millimetres long, they look like specks of dust at first glance, but on closer inspection are perfectly formed little ants.  This bunch is a minor infestation running around the kitchen surface where I’m staying in California – or rather an ex-infestation, as I’m afraid we had to zap them.  Native to most parts of the U.S.A. – for sure we don’t have anything like this in Surrey – they’re also known as thief ants for their behaviour of stealing food from other ant colonies.  They also like grease.  The UK 20p piece is for size comparison – it’s about the size of a U.S. nickel.

Naturally, there’s also a Grease Ant Movie.  Shot in low light with the iPad camera, so excuse the less than National Geographic production values: