Tuesday, March 24, 2009

Sexual Dimorphism in 5 North American Blackbirds (family ICTERIDAE)


... because I like Blackbirds, that's why!

Red-winged Blackbird (Agelaius phoeniceus)


Male


Female


Yellow Headed Blackbird (X. xanthocephalus)


Male


female


Boat-tailed Grackle
(Quiscalus major)


Male on Mexican Sabal Palm (Sabal mexicanus)


Female


Brown-headed Cowbird (Molothrus ater)


male


Female


Baltimore Oriole (Icterus galbula)


Male with Mulberries


Female


Male and female Baltimore Oriole

Friday, March 20, 2009

RANDOM ANURAN SPOTLIGHT no. 2

A series of posts on random and awesome anuran species for those that love Amphibians.

Colorado River Toad (Bufo alvarius)


Nothing says love, like the grimace of an enormous toad. The Co. River Toad is best known for its potent skin excretions, which have been used by Native Americans as a hallucinogenic substance in cultural and religious ceremonies for hundreds of years.


Also known as the Sonoran Desert Toad, these toads are found in and around water sources in the Sonoran Desert region in Southern Arizona, SE Calif, and SW New Mexico.


This is a sizable toad, that can reach up to 7 inches in length and achieve a hefty girth. As with most frog species, the females are larger.


Notice the sizable paratoid glands (poison producing glands found behind the eyes) that are found in most toad species.


What 're YOU lookin at vato? Like all species of anuran (frogs and toads), they are carnivorous... eating any animals small enough to grab (with their mouth) and swallow.


Breeding takes place in temporary pools formed by the considerable summer rains.


The brownish tadpole will take about 1 month to metamorphose into an adult.


Fringed Leaf Frog (Cruziohyla craspedopus)


The Fringed Leaf Frog is found the rainforests of Western Amazonia; in Brazil, Ecuador, Peru, Columbia, and Bolivia.


This frog is rarely seen, because it spend most of its time high in the trees where few people venture.


The pattern and "fringes" on the edges of the treefrogs limbs help it to blend in with the moss dappled surfaces of the trees and leaves they live on


The arboreal frogs only descend to the ground when cavities in fallen logs fill with water during the breeding season, where they lay their eggs.


Holy Cross or Crusifix Frog/Toad (Notaden benettii)


Crucifix Toads are found in arid areas of Eastern Australia. The name comes from the quite discernible cross pattern on the back. Although, I'm not sure how religious they are. You might think that the bright colors are to warn off predators, because of some powerful skin toxin...


However, in the case of Notaden, they defend themselves with a very sticky glue like skin secretion that gums up the mouths and fur/feathers of would be predators. The males will also glue themselves to the backs of the females temporarily for mating.


Though, in this close up picture it may seem an enormous frog, The Crucifix Toad reaches a length of only 2.5 in(male)/2.7 in(female). Their small mouths are perfect for a diet of ants and termites.


A small male calls to prospective mates. As with most anurans, it is the males that sing or call to the females. The females are believed to judge fitness as a mate, initially, on the quality of the song.


Mating usually occurs during the rainy season, when the frogs emerge from their subterranean burrows (where they have been encased in cocoons made from hardened skin secretions, to keep from losing body water).


These tiny froglets hop around in the shallows of the temporary desert pool where their parents deposited them as fertilized eggs. These pools are the main source for breeding and tadpole deposition for anurans that live in arid zones.


Side Note:

For many Anurans, that are in families other than the True Frogs (Ranidae) or True Toads (Bufonidae), you may see either the word "frog" or "toad" used for it. This can be arbitrary, based on evolutionary relationships with the aforementioned families, or based simply on appearance. Many people tend to call shorter, fatter, and/or anurans, "toad", while referring to more stream lined smoother anurans as "frog". Some people refer more terrestrial species as toads, while referring to more aquatic species as frogs. Often different people will refer to the same species by different labels. (ie. Crucifix Frog or Crucifix Toad)


Malayan Painted Toad or Malayan Painted Frog (Kaloula pulchra)?


Depends who you ask. They're fairly terrestrial and in the family Microhylidae (the Smallmouth Toads/Frogs), which is evolutionarily close to the True Toads, so I'm going with "toad" on this one.

Monday, March 16, 2009

RANDOM ANURAN SPOTLIGHT no. 1

The beginning of a series of posts on various species in the Order ANURA, the frogs and toads...

Yellow Spotted or Boulenger's Tree Toad (Pedostibes hosii)



As the name suggests, Pedostibes climbs into trees. This is not normal behavior for the usually land based toads. Notice the enlarged adhesive toe discs for better grip.


Someone is not amused with your fake British accent.


As with many members of the True Toad family (Bufonidae), The Yellow Spotted has prominent cranial ridges and tuberculous (bumpy or warty) skin.


Throughout its range in Southeast Asia, this toad can vary in color from green with yellow spots to orange or brown.


Let's get it on Froggies! The smaller and more drably colored male amplexes (amplexus - the breeding embrace of anurans) the female in this laboratory container.


One of the elusive tadpoles of P. hosii in an aquarium in Borneo


Tomato Frog (Discophis antongilii)


The Tomato Frog is endemic (only found there) to Madagascar (as are 99.6 % of the frogs in Madagascar), where it is found in a variety of habitats near water.


Punks step up to get beat down! The Tomato makes a threat posture, lifting itself up and inflating. If seized it can release a mildly poisonous and sticky solution from its skin.


As with all frogs, when swallowing they must use the backs of the eyes to help push down food, a this Tomato Frog does. Anurans do not have the same esophageal muscles we do to aid in downing food, usually small invertebrates.


As with many of the Malagasy (from Madagascar) fauna (animals), they are listed as near threatened from habitat destruction.


Amplexus shows us a comparison of the male and female, both in size and pattern. The male is on top, and will not release sperm until the female releases her eggs in water. Fertilization is usually external for Anurans.


Coronated or Crowned Treefrog (Anotheca spinosa)


THEY GIVES US THE PRECIOUS!!! This entirely arboreal species of frog emerges from its lair.


The spike like projections found on the head that give the frog its name


The juvenile frogs lack the crown.


Crowned Treefrogs are found in Cloud Forests (montane rainforests) in the lower half of Central America (from Costa Rica to Panama).


The adults mate in tree cavities and bamboo sections filled with water, thus not even coming down form the trees to reproduce, as many arboreal anurans do.

Friday, March 6, 2009

GALLERY OF EXTINCTED ANIMALS no. 4 - Birds Birds Birds

A continuing study in animals lost forever...

Heath Hen (Tympanuchus cupido cupido)

The Heath Hen was the 1st endangered bird that post-European settlement Americans made a concerted effort to save from extinction. Ultimately, they failed. The last birds on the Mainland U.S. were gone by 1870, and the last of the species died on Martha's Vineyard in 1932. A couple of centuries of over-hunting for meat and several unforeseen calamities during the years of conservation brought their numbers too low to recover.



This illustration depicts males calling and displaying their cheek pouches and ear plumes, much as the other species of Prairie Chicken in the U.S. do. They would gather at leks, areas where multiple males display for prospective mates.


They were actually quite common in the Colonial Era, and were commonly eaten until conservation measures were taken in the early 20th Century. Heathies were considered poor quality meat, but were readily available in their range from New England to Virginia.


A view of the erected ear plumes and orange cheek patches (which would be inflated during display).


During the years of conservation on Martha's Vineyard, disasters such as intense wildfires, poachers, severe weather, and inexplicable increases in Goshawks befell the birds in their preserves.


There is still some discussion as to whether the Heath Hen should be considered a distinct species or a subspecies of one of the other 2 species, the Lesser and Greater Prairie Chickens.


Kona Grosbeak or Kona Finch (Chloridops kona)

The Kona Finch is a bird that was not well known by people. There is only one written observation of the bird's habits, by naturalist Scott Barchard Wilson in the early 1890's, and the native people of the Kona Coast of Hawaii Island weren't familiar with them at all. They seemed to be already fairly rare, when Europeans first encountered them, and their elusive habits in the mountainous terrain in the area didn't help. No one is really sure why they went extinct. The last one was seen in 1894.


Kona Finches had thick cracking beaks, to aid in opening the heavy seeds they ate. Wilson's description of the bird was of a fairly sluggish inactive animal, that seldom sang.


There exist no photos, nor well preserved mounts of the birds. Can you spot what's wrong with this picture? Hint, read the above picture caption. This artist was probably confusing the bird with one mentioned in the next caption.


The Kona and 2 other closely related birds in the Kona Coast area, the Greater Koa and Lesser Koa Finch, went extinct in the 1890's from unknown causes. The Kona Grosbeak was the smallest of the 3.


Greater Koa Finch (Rhodacanthis palmeri), last seen 1896, sometimes indulged in caterpillars, as well as their usual diet of seeds. This was the noisiest of the 3 birds. They fed mostly on the seeds of Koa trees, thus the name. Notice the sexual dimorphism, the adult males having reddish plumage.


Lesser Koa Finch (Rhodacanthis flaviceps), last seen 1891, was in habit quite like the Greater Koa Finch, only a bit smaller and not as sexually dimorphic.


Labrador Duck (Camptorhynchus labradorius)

The Labrador is the only DUCK to go extinct in, and the first BIRD known to go extinct in North America since European settlement. The causes for the loss of this animal are not well understood, and probably fairly complex. The Last one was seen in 1858 in NY State.


The Labrador Duck was often referred to as the "Skunk Duck", because of its coloration. They were also referred to as the "Pied Duck", as were 2 other birds off of the NE U.S. and Atlantic Canada, which makes historical investigations of the bird difficult.


The female was less dramatically colored.


The shovel like bill was well formed for dislodging and seizing shellfish (Bivalves, like muscles and clams), which were the main part of its diet. Its believed that the dramatic decline in North Atlantic shellfish populations in the mid 1800's (due to over-harvesting by humans) was a major cause contributing to extinction.


Sad museum specimens are the only way you'll ever see one in person.


Because of their foul taste and speed of putrification of the flesh, meat seeking and recreational hunters didn't often go after them.


Another possible source of the species decline may have been hunting for the millinery trade, or the trade in feathers for the lady's hat industry.


The eggs, as well, were sought after, and may have been over-harvested, leading to decline.


Because the Labrador went extinct before much scientific study of the species could occur, little is known of its habits and breeding ecology.


Another of John James Audubon's studies of North American birds, as with most of his beautiful plates, these were rendered from birds he shot, then painted , often in location in the wild.