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01016_RobinEggBlue-lI realized that this blog has done a poor job of addressing the color blue—which is one of people’s favorite colors.  Today therefore, in an early tribute to spring (which may eventually get here this year) we are writing about one of the most beautiful colors of blue there is.  The color takes its name directly from nature—from the nest of one of the most beloved birds of North America, Turdus migratorius, the American robin.  American robins are actually members of the thrush family: they superficially resemble old world robins (which are flycatchers), so European colonists lumbered us with the inaccurate name. Robins are migratory passerine birds which hunt the ground for worms and other small invertebrates as well as fruits and berries. The robin is famous for its jaunty orange breast, its vivacious style of hopping, and, above all, as a harbinger of spring.

robins-nest-web-1There are similarities between humans and robins. We are both bipedal omnivores.  Robins are unusually successful—perhaps more so than any other common passerine bird.  Additionally they are highly social and flock together to stay safe at night. However this blog post is not about the songbird (after all, when it comes to ornithology, ferrebeekeeper is solemnly devoted to galliformes and waterfowl), instead it is about the color of their eggs: robin egg blue.

eb4700e8774c6798119fd6c84a38ce55Robin egg blue is a lovely pale sky blue with a hint of green.  The name of the color has been in common use since the nineteenth century. The color appears everywhere: in crayola crayons, Tiffany jewelry boxes, spring frocks, giant bridges, and Air Force fighter jets.

Robins lay these eggs in nests which are 1.5 meters to 4 meters from the ground (5 to 15 feet).  Because the nests tend to be in low shrubby trees many children have had sad experiences watching things go wrong.  Fortunately robins are prolific parents and can sit as many as three clutches of eggs each season!  They also start nesting and laying early in April.

robin's eggCoincidentally, the aviary at the Bronx Zoo strongly featured the robin’s egg as an illustration of the powers of contingency and fatality in the world.  Visitors walk into a room with a large wall covered in hundreds of photos of lovely robin’s eggs. The next room has photos of robin hatchlings in exactly the same grid layout, but the little birds are far fewer than the eggs were: every space which lacks a hatchling photo features a little obituary of how the egg failed (or was eaten by a predator, or broken in an accident).  The next room features even fewer photos of fledgling birds–as nature continues to winnow out the unlucky.  The final room has only one or two adult robins to produce another suffusion of eggs.

robin eggI was at the zoo bird house many years ago with my then girlfriend and each of us randomly chose a particular egg in the first room to see how we fared.  My ex-girlfriend fell out of the nest and was eaten by an opossum almost immediately (!).  I survived to adolescence (which was quite rare) but was sadly captured and devoured by a hawk—so at least I had a thrilling aerial death!

Sometimes it seems like it's all hawks

Sometimes it seems like it’s all hawks

As I go through life, I often find myself thinking about the room of eggs. Although troubling, it resonates in a great many ways. The zoo meant it as a (quite effective) illustration of nature’s cruelty and caprice (and of the strategy of producing lots of offspring), but it also portrays larger themes of luck, planning, adversity, and perseverance.  In an even larger sense it represents how amazingly lucky any of us are to be here after billions of years of predation, foraging, and trying to impress fickle mates.  Yet we are indeed still here. We are the astonishingly lucky eggs who have survived by pluck and luck.  Spring will come again—and good times with it.  It’s time to buy some jaunty robin egg blue clothes and plan the next series of adventures and projects!

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Monito del monte (Dromiciops gliroides)

Monito del monte (Dromiciops gliroides)

Monito del monte (Dromiciops gliroides) is a tiny arboreal marsupial native to the temperate rainforests of Chile and Argentina.  The name “Monito del monte” means “little monkey of the mountain” and although the tiny marsupials are not even remotely related to primates, they are clever and deft.  During the cold winter months the animals hibernate in little ball-like nests which they build out of waterproof leaves and line with moss.  Like the more familiar marsupials of Australia, the females have pouches where they nurse their litters of up to four offspring.

Monito del monte (Dromiciops gliroides) with tree snail

Monito del monte (Dromiciops gliroides) with tree snail

The adult animals prey on small invertebrates which live in the trees but they also supplement their diets with fruits and seeds.  A particular species of Loranthacous mistletoe (Tristerix corymbosus) has evolved in conjunction with the monito del monte and relies entirely on the animal to spread its seeds.  This is noteworthy because “scientists speculate that the coevolution of these two species could have begun 60–70 million years ago.”  The monito del monte is not some rodentlike offshoot of the marsupial line, it is a close analog (and direct descendent) of the basal line from which all marsupials spring.

Monito del monte (Dromiciops gliroides) with human for scale

Monito del monte (Dromiciops gliroides) with human for scale

In fact, like something out of a gothic novel, the monito del monte is the only species of the sole genus of the last family of the exceedingly ancient order Microbiotheria.    During the dawn of the dinosaurs, South America, Antarctica, and Australia were amalgamated together as a supercontinent Gondwana.  The offspring of the original marsupials spread from South America, across Antarctica, to Australia, but then the continents drifted away from each other and evolution took a different direction in each ecoysytem.  The monito del monte remained in the same sort of forest as its ancestors and changed least over the years.

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Speaking of which, the Valdivian temperate rain forests where the monito del monte lives today are themselves a remnant of the great forests of Gonwana.  The trees and plants which live there now are most closely related to the living plants of Australia, New Zealand, & New Caledonia, but they are closer still to the fossilized forests which lie beneath the glaciers of Antarctica.  The Valdivian forest is the closest thing surviving to the great forests which once covered the iced over southern continent.

Valdivian Temperate Rainforest

Valdivian Temperate Rainforest

The ancestors of the monita del monte—and of all other marsupials—originated in South America and spread through the Antarctic forests to Australia before the continents drifted apart during the Cretaceous.  When the continent broke from Australia and drifted south into the prison of the circumpolar current during the Eocene, the forests died and Antarctica became an otherworldly landscape of ice.   Yet if you wish to know what the sweeping temperate forests of Antarctica were like you can visit Chile and watch the most ancient marsupial among the tree ferns and araucaria trees of the Valdivian forest.

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An Iridescent Wasp on a Linen Tablecloth

Today I would like to start a brand new animal category concerning the most gifted of the social insects, the superorder Hymenoptera, which consists of wasps, bees, ants and sawflies (along with some other oddballs which are less frequently mentioned).  Hymenoptera are arguably among the most successful creatures on the planet.  Their behavior can be almost embarrassingly humanlike and they are famous for building elaborate constructions, going to war, taking slaves, farming fungi, and crafting rigid city-like social hierarchies. However, of all life forms on earth, the hymenoptera are some of the most vividly alien: cuttlefish do seem downright cuddly when compared to the horrifying digger wasps.   A sociologist could happily draw parallels between a bee hive and a city until he looked at the details of bee reproduction, at which point he would probably break down and weep.

The Hymenoptera are not as ancient as either the mollusks or the mammals (if it is fair to compare an order with a phylum or a class).  They originated in the Triassic and did not develop the successful social organization which is now such a defining feature until the late Cretaceous.   The first hymenopterans were the xylidae, a family of sawflies with a minimal presence on earth today but with a long pedigree. These first sawflies fed on the pollen and buds of the conifer stands beneath which the first dinosaurs developed (and under the roots of which the first mammals cowered).  The rise of the flowering plants in the Cretaceous led to a leap-forward for these pollen-eaters: complex flowers then evolved in tandem with the hymenopterans. It was also during the Cretaceous that the ants and termites split from the vespoid wasps.  The earliest honey bees of the familiar genus Apis evolved at the end of the Eocene bt they were preceded by all sorts of hymenopteran pollinators.

A Sawfly Fossil (Hymenoptera: Symphyta)

I mentioned above that, for all of their familiarity to us, the Hymenoptera are disturbingly alien.  In fact as I have been writing this comparatively tame post, a dreadful sense of formication has stolen over me and I find myself brushing phantom ants from my limbs and feeling the terrible pang of yellowjacket stings from childhood.  The hymenoptera are frequently the basis of the extraterrestrial enemies in science fiction.  Although people are occasionally stung to death by wasps or ripped apart from within by driver ants, it is something larger and less tangible which makes the hymenoptera such reliable villains. I have watched the soldier bees snip the wings off of wasps trying to invade my grandfather’s bee hive and then toss the invaders’ writhing bodies from the painted ledge—all while a river of worker bees went out and came back laden with pollen.  There is an alarming touch of civilization to these social insects: a hint that they are utilizing the same kinds of organization and communication which have made humans such a success.  And, in fact, the social insects are a huge success—ants alone are estimated to constitute a substantial portion of the animal biomass of earth (to say nothing of termites, bees, wasps and the rest).

Yellow Jackets on a Coke Can (photo by the fearless Alan Cressler)

Of course this success has broad ramifications. The hymenoptera are everywhere in nature and they also play a huge part of human culture. Indeed the very name of this blog is a play on words between my surname and the noble art of aviculture.  Without the bees, we would not have much in the way of fruit or vegetables.  Not only would this be a disaster for human farming—just contemplate how many other creatures rely on those fruit!  Similarly the ants bulwark an entire portion of the ecosystem by scavenging the tidbits out of fields and forests.  Writing about the hymenoptera may be an itchy, antsy business but it is a well-merited study.  This group of insects is pivotal to life on dry-land as we know it.  The biblical promised land was one of milk and honey.  There would be no milk without mammals, but there would be no honey (and precious few mammals) without the hymenoptera.

A beekeeper completely covered with swarming honey bees in a “bee man” cantest in China

The Eel-tailed Catfish (Tandanus tandanus)

Last week, I wrote about the great builders of the animal world, the beavers. But of course all sorts of other creatures build things.  The Eel tailed catfish (Tandanus tandanus) lives in the Murray-Darling river basin of Eastern Australia where the creatures’ nest-building habits are costing them dearly.

The eel-tailed catfish is from the family Plotosidae (in fact it is a close relative of the striped eel catfish) and like other family members its most distinctive feature is a continuous fin margin surrounding the posterior half of their bodies—aka an eel tail!  These catfish prefer to live on the gravel or sand at the bottom of lakes or slow-moving rivers.  They eat crayfish, yabbies’, worms, mollusks, insect larva, and other smaller fish.

An eel-tailed catfish nest (the parent is in the middle)

A week or two before spawning, pairs of eel-tailed catfish build nests for their eggs. The fish construct these torus-shaped structures out of sand and pebbles and, once the female lays the eggs, one or both parents stay with the nest to guard it and to aerate the eggs until they hatch.  Unfortunately, because of drought and agriculture, the Murray basin is rapidly drying out and silting up.  As the pebbles and coarse sands which the fish use for nests are smothered with slimy silt, the species has been declining.  Additionally, eel-tailed catfish are being out-competed by invasive carp which were introduced in a hare-brained aquiculture scheme.

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