Firefinches
290 million years PE, on the savannah woodlands, a new evolutionary arms race has developed between herbivores, including gantuans and thorngrazers, and a new lineage of poisonous sunflower-descendant herbs called flameflowers, which have evolved to defend themselves against this destructive plant predator and so gain a competitive advantage on the plains over grasses. These plants produce a toxic brew of terpenoid chemicals in their sap, which burns the mouth tissues of herbivores when chewed, similarly to the effects of the blister beetle's secretions on Earth. This works reasonably well to protect these new plants from their grazers, but their appearance has had further-reaching consequences among other animal life here as well.
Firefinches are a clade of poisonous mowerbirds. Their lineage diverged from others before 285 million years PE. These birds have evolved to sequester the chemicals by feeding upon flameflowers, to which they have become immune through co-evolution and a more rapid rate of reproduction than thorngrazers that has allowed their species to experience a greater number of adaptive mutations in the same span of time than larger animals would be able. Over the last seven million years, these plants have become much more poisonous than they were when the generalized herbivore ancestors of the firefinch first began to nibble on them, and the firefinch has become increasingly resistant, so that they are now the only vertebrates which can consume these plants without any ill effects - and these are now the bulk of its diet. Firefinches store the terpenoids in their bodies and excrete them, even more concentrated than they occur in the plant, through the oil of the preen gland above their tails. Simply through the regular process of preening, they coat their plumage in the chemical which renders them highly poisonous to all vertebrate predators. Once colored green to match the grasslands they dwell on, firefinches now exhibit string aposematic coloration: bright yellow, red, and black patterns that warn of their deadly touch. Anything that so much as touches one will break out in a blistering rash, so that the firefinches are all but untouchable. This has had the effect of letting them become extremely bold and defiant of typical norms: living mostly outside the food chain, these birds are aggressive and fearless - none more so than the fanged firefinch, which has been compared to an avian wasp.
Firefinches live in groups, like all mowerbirds, but do not make stick nests in trees. These birds evolved from a lineage of mowerbirds that evolved to construct mud-based nests on the sides of large rocks, cliffs, and the trunks of cementrees as a result of heavy competition for easier nest sites with other species. These bowls would harden in the sun into a well-protected shelter, and over time, their constructions grew from simple bowls to more complicated nests with multiple interior chambers, used by multiple pairs. As the firefinches evolved their toxicity, the nests of some species dropped from elevated sites simply down onto the ground, for they had fewer predators to worry about, and there they became like the nest structure of the fanged firefinch: a large tower-like mound, up to ten feet high and five feet wide, in which many pairs of birds may raise their young together in close association in a uniquely cooperative manner, so that the total population in residence can surpass 200 birds. Adult firefinches are safe from predators - their secretions protect them; chicks, though, are usually born defenseless, for they are typically fed insects - not flameflower foliage - until they leave the nest. This means that nest robbers are a very real threat until the babies can acquire their defenses as they adopt their adult diet between one and two months of age - and this is where the communal nesting habit of these species comes into play. All firefinches live in colonies so that there are always adults present to defend the creche of young from enemies, even with many birds away gathering food. With little inhibition, these tiny birds face foes a thousand times their size without a second thought, seeking to brush against the eyes or noses of their attackers and irritate their mucous membranes with their secretions.
Fanged firefinches, though, are the worst of the lot. This species has evolved four extra-long serrations on their plant-cutting bills which function like fangs: by gathering preen oil, they coat their beak in chemicals and then bite anything which bothers their nest, injecting them into their enemies, and turning their defenses into an offensive venomous bite. Not only potential chick predators are swarmed by aggressive flocks of this bird, but anything that comes close to the nest at all, even the largest land animals, the cygnosaurs, which could carelessly knock their nests over without even meaning to. Fanged firefinches will take on anything which lives to defend their homes, attacking the faces of giants and driving away all comers - they are perhaps the most aggressive bird that has ever lived, for they have lost all consequences which would otherwise reign in their behavior. And being a newly-evolved lineage yet, no new limits to their success have yet evolved; nothing eats firefinches, and little is immune to firefinch secretions, except for themselves. These birds have thus spread across Serinarcta's open plains incredibly rapidly, building their nests, and menacing anything that approaches them. Yet their aggression has positive impacts too, with their towers influencing the behavior of the cantankerous cygnosaurs which otherwise strode with little fear themselves anywhere they pleased. Now the firefinches influence the ecosystem in turn, with the areas around their nests keeping such herbivores away, and providing safe havens for the growth of lush and beautiful plants that would otherwise not be able to survive in the open due to grazers.
Firefinches are feisty, but even this most hostile bird species is not completely unreasonable. It takes a lot of energy to attack everything that comes nearby the nest, and that energy must be recouped by feeding - and the plant diets of the adult aren't high in calories, so they must spend much of their time eating. To save energy, all species produce a warning call when agitated which sounds remarkably similar between them, a high pitched buzzing that serves to tell other animals that they are too close and need to move away. This is already exploited by other intelligent birds, especially chatteravens, which can imitate the sound to scare predators away from their own chicks, or even to drive animals away from hard-earned food so they can steal it. Adaptations like these show that life is already adapting to the firefinch in some ways, and over time, their reign of terror may be reigned in somewhat, though severe climactic changes in the near future may complicate things; whether, or how well, these birds will weather the next era remains to be seen.
For now, in the late hothouse age, the firefinches are a specious and diverse lineage. Though the fanged firefinch, for having evolved "teeth", may be one of the most distinctive, it is just one of a varied group of hothouse birds. A sampling of other extant species, each unique in its own way, is presented below.
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Flareakeets are a genus of firefinches with distinctively hook-shaped bills. Bigger than the typical firefinches of the genus Igniplumus, they are adapted to feed on coarser foliage, using their beaks to cut and tear the strap-like leaves of larger blistergrasses, needlenode trees, and elkhorns. Their toxicity, combined with their larger size and equally belligerent temperament, often allows these firefinches to nest in exposed places, and many will lay their eggs and rear their chicks in little more than depressions on the ground. Making no effort to hide their nests, even their eggs are colorful - bright red, like the plumage of the adult, and unlike other species, even the albumen of their eggs has become infused with defensive cantharidin. To break open one of these eggs would be like consuming the concentrated extract of many flameflowers, and so these eggs, like the plants their defenses originally came from, are left quite alone even when the parents must leave them to find food for themselves. Animals that crack one open will not likely do the same thing again twice, if they survive the resulting burns in their mouth at all. Because the female concentrates toxins in her eggs, not just her preen oil, her chicks are poisonous from hatching, in contrast to other firefinches. Thus they, too, are boldly marked with vibrant black and orange striped down, and when threatened they hiss and flutter their wings to turn their banded markings into a dizzying warning display resembling a swarm of bees. Usually nesting in colonies, flareakeets raise their young in open, upland environments with little tall vegetation, and the chicks simply sit upon the ground until able to fledge around 5 weeks of age. Collectively, dozens of chicks huddled up near one another can produce a frightening loud hiss and a confusing visual spectacle, enough to frighten away even larger herbivores like thorngrazers. The young are only vulnerable to animals like cygnosaurs, so large as to not notice their displays and liable to simply walk over them obliviously, but it is to avoid them that the flareakeet has come to make its nests in places with little food nearby to support such giants, and so in places they are unlikely to pass through.
The coalcapped flareakeet, named for its black-feathered head that contrasts its red and yellow plumage, makes its home in Serinarcta's Hyperborean Raindesert. Here, in this vast sand dune system east of the Polar Basin where cygnosaurs and other such clumsy giants are virtually absent, it feeds mainly on dune-growing elkhorn flameflowers. It forages in pairs or small groups and feeds mostly upon the leaftips of these plants, which grow continuously from their bases in many species. Elkhorns are very toxic, and though flareakeets are resistant, even they avoid the newest growth of their food plants which contain the most poison. By trimming the tips of the leaves instead, they find a more palatable meal, but one still virulent enough to render them and their eggs toxic to predators. The large, hooked beak of these species lets them trim through these older leaves, which are too hard for smaller firefinches to tear and chew. Like most mowerbirds, these firefinches are still to some degree omnivorous and chicks require a higher protein diet to grow. During nesting adults also feed on insects, including those which also feed on flameflowers, which ensures the chicks remain toxic. Even young flareakeet nestlings also eat a fair amount of plant food though, especially grass seeds which are regurgitated by the parent; though they are not poisonous, they are a readily available, and relatively digestible source of energy for the young. Depending on their exact diet in infancy, flareakeets may or may not remain poisonous for their whole childhood; toxins acquired through their eggs can be depleted over time if they are fed a diet high in grass seed or non-toxic insects, but the birds rapidly regain their defenses once weaned onto their adult diet. But for a potential predator, the small chance a chick may be worth eating is not a risk worth taking, and all chicks are viewed as dangerous, because one wrong guess could be fatal.
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The bloodybill firefinch, closely related to the fanged firefinch, is a small, thrush-like bird, about seven inches tall. Like others of its genus, it is quite social, and colonies nest communally, but only seasonally. Its plumage is primarily made up of brightly contrasting yellow and black bands, with some green in the wing area, and red on tail, wrists, and cheeks. A prominent feather crest is present, which can be raised or lowered at will, and the feet and bill-tip are red. The bright patterns on its plumage indicate, like all firefinches, that it is poisonous. But bloodybills, strangely, don't feed significantly on blistergrass nor on other flameflowers. They acquire their defenses by stealing them from other firefinches that did the work to collect them from their source. Bloodybill firefinches hunt and kill other firefinches for their poisonous secretions, ripping apart their preen glands and covering their own feathers in the oil. The rest of the carcass is then eaten; bloodybills, unique among adult firefinches, are carnivores.
These firefinches exploit the lack of predators of their lineage by becoming them. Their own in-built immunity to flameflower toxins now allows them to feed on their relatives, finding a more nutritious flesh diet without sacrificing their own defenses against other enemies. Their predatory habits originated as an outcome of territorial aggression toward related species and opportunistic consumption of rivals killed in conflicts. Now, they seek out rival species in groups and raid their nests, killing chicks and brooding females while trapped in the nests. Intelligent and coordinated, they eye their prey and wait for flocks to disperse to forage, striking when their targets are left unguarded. They smash and grab, working as a swarm that decimates and dismembers any other firefinches they can catch. Against this enemy born from within, other firefinches have no advantages. One on one, the bloodybill is usually slightly larger, and it can overpower most relatives in a fight. Though its beak is not so sharply serrated as the fanged firefinch, it does show four precursors to that species' "fangs" at the tip of its own bill, and it uses these to puncture the throat of its prey and bleed them out. Other birds are torn apart through the efforts of multiple individuals, pulling and twisting them limb from limb into pieces they can carry away in flight. It often has a numbers advantage against flocks of its prey for unlike other firefinches, it is nomadic except when nesting, and so large groups can form which cover great distances daily, descending on new firefinch nests and ransacking them, then departing. The bloodbill is one of the only vertebrate predators any firefinch has, and its acquired taste for near-cannibalism now controls the population of its otherwise nigh-unstoppable relatives.
Nesting in the bloodybill requires a shift to territorial living, and so a reprieve from marauding the plains and terrorizing other firefinches. Colonies usually settle in the large, tower-like baked mud nest of another firefinch colony they have slaughtered, and while breeding much of their diet comes from non-toxic birds, as well as small tribbats and larger insects. Now they become more vulnerable, for they do not sequester their defensive chemical on their own, and without other firefinches to steal their preen oil from, they become non-toxic in a matter of weeks as this oil is lost from their feathers. Though they are highly aggressive at all times, other predators seem to recognize when the bloodybill is nesting it is back on the menu. Everything in nature must find a balance, and for the bloodybill, their comeuppance comes when they raise their chicks; many of them are taken by enemies before reaching adulthood, and so too are some of the adults killed whilst brooding their young, exactly as they would do to other firefinches. It's really nothing personal - just the game of survival, where nature is red in tooth and claw.
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A more typical example of a firefinch, the red and golden hued masked firefinch is also one of the most abundant species, forming flocks of several thousand when foraging, and living in communities of several hundred breeding pairs in large shared nests. Adults of this species are herbivorous and feed nearly exclusively on the leaves of blistergrass, while chicks are fed on insects and a small amount of grass seed. Masked firefinches have long, narrow and finely serrated beaks, suited to cut through the strap like foliage of their food plant like shears, but their small adult size - a standing height of scarcely five inches - prevents their feeding on larger, more armored foliage. This species of firefinch is known for its habit of snipping and peeling the leaves of blistergrass back in narrow thread-like strips and using them to construct its nests, providing additional protection to its chicks, born without their acquired poisonous preen oil.
Masked firefinches are one of the least aggressive of their genus and only attack if threatened, and even then will flee unless protecting their chicks. If pressed, they will dive at enemies in large numbers and swipe their wing plumage against the eyes, seeking to brush these most sensitive regions with their toxic preen oil, which results in a pepper spray-like response that can dissuade even the biggest enemies from harming their young. Only their relative, the bloodybill firefinch, is a significant threat, but the masked firefinch has some interesting adaptations that may help it to escape even this foe: nesting female masked firefinches, when under attack by maurading bloodybill firefinches, emit powerful pheromones normally suggestive that a female is receptive to mate, and this may serve to confuse male attackers and stall them. Mowerbirds have a strong sense of smell, relative to most sparrowgulls, and as these species are all closely related, this sudden stimulus can be enough to cause an attacker to switch into a different behavior pattern and, instead of killing the mother and chicks, attempt to mate with her. At the least, this buys her some time to escape, but it also provides precious time for her own mate or others in the colony to fend off the interloper.
Taking advantage of a brief window in which he is distracted, several males may corner and successfully kill their would-be predator, and so save the female and her nestlings. Masked firefinches live in such large colonies as a response to bloodybill predation, and distress calls of any individual will trigger collective response from other adults nearby even if they are unrelated. Only by allying together as a whole can they challenge their collective enemy, and by doing so, despite being the most common firefinch, they are one of the less preferred targets of the bloodybill, and most likely to fend off an attack without substantial losses. Hybridization between the two species occurs as a result of their unusual defense mechanism, but such hybrids rarely survive to adulthood, as the two have evolved significantly different nutritional requirements despite their close kinship. A vegetarian diet is unsuitable for the hybrid, and this species weans its young sooner, so that once cut off from a nestling diet of insects, they usually starve trying to eat the leaves the adult favors.
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The flamboyant firefinch is the only member of its genus endemic to Serinaustra, and is both visually and behaviorally distinct enough from other members of its genus that it could be classified in a genus of its own; it is included in Igniplumus, however, because it is no more distantly related to other species within it, than those are to one another. A denizen of forest edges rather than grassland which island hopped here through the Trilliontree archipelago, it is now a strongly terrestrial bird which forages on the ground and flies only when absolutely necessary. As such, it is usually only faced with predators from above, and so on the topside of its wings, on its head, and on its tail it flashes a bold red, yellow, and black pattern of contrasting spots and bands, like other firefinches. Below, though, the male is a brilliant violet on the throat, blue fading to bright green on the flanks, an uncommon example of sexual dimorphism among the firefinches, and which the male uses to court a mate.
Unlike gregarious grassland firefinches, flamboyant ones are relatively solitary, living only in pairs. Males lower their heads and sing to draw in mates, a low-pitched buzzing call that would be more melodic to their own ears than those of humans. If a female - which is red and gold all over her body with no blue at all - approaches, he soon dances around her. He flutters his wings, spreads his tail, and raises his song into a series of harsh staccato chirps, and if he is up to par, she may accept him; the pair then stays together for a few seasons to breed before the female, not inclined to settle for longer than a couple of broods, is likely to move on and seek a new mate, and so the population remains genetically diverse. The nest is constructed of mud and dried plant material in a domed mound on top of a forest branch, and only a single pair dwells within at a time.
This firefinch feeds mainly upon the vining flameflowers, which are as a rule fleshier and easier to cut and graze than are those of the stiff-stemmed flameflowers which are less common on the southern continent. Flareflags, including relatives of the huge and lethal suncatcher of the north pole, are a major constituent of its diet, as they are abundant here in the southerly wetlands. The flamboyant firefinch grazes them while hopping on the ground, picking at the bases of their tall leaves until they are felled, and then cutting out the leaf tissues from between the ribs so as to leave the foliage skeletonized before moving on to cut another leaf. When breeding, the diet switches mainly to small invertebrates which are often collected close to water. Both sexes are territorial, defending a small home range from others of their species. The chicks are driven off at an early age, shortly after fledging; they are fledged a dull green color in order to let them hide in the undergrowth until they have acquired their defensive chemicals from their adult diet. Around 5 months of age, they molt into their vibrant adult plumage and become less cryptic, gaining confidence in their total lack of predators, as there are no cannibal relatives to menace them here as exist further north.
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Unlike the typical firefinches, flareakeets have produced several endemic Serinaustran species, perhaps because they are larger and thus more likely to survive the trip overseas. The vulturine flareakeet is one of the most aberrant, immediately recognizable for the entirely featherless, bald head of the adult. This adaptation likely arose as this species of firefinch began broadening its diet with fruit, particularly those of umbrellivy vines, which have notoriously sticky seeds so that the plants' progeny can be carried on bird's plumage and later scraped off on a new tree branch where they will take root. The vulturine flareakeet, without head feathers, keeps itself clean while feeding, and can more quickly wipe its face after a meal without injuring itself as it might if when scraping off the sticky seeds, it pulled a few feathers out in the process, as is common in other birds feeding on this diet. Both sexes retain a small tuft of expressive feathers on the forehead, which can be raised or lowered, and which is used to indicate emotional state.
Vulturine flareakeets are social birds which move in flocks of ten to more than fifty, feeding on a varied diet of plant foods but which is still high in the foliage of flameflowers, from which they acquire their toxicity. Like the flamboyant firefinch, vining flameflowers are the primary type included in their diet. Because it feeds on a larger variety of food than many firefinches year-round, it is somewhat less toxic, and is more distasteful than deadly, though enough so that it still has few major predators, as there are plenty of less spicy birds around to feed on instead. This species of firefinch constructs large stick nests in the treetops, rather than using soil and mud to make a home, and its nests are quite complex, communal, and can reach weights of a ton or more after generations of shared use and continuous additions over many years. In each nest single monogamous pairs care for their own broods, but the whole colony will fend off predators; like fanged firefinches, vulturine flareakeets bite enemies with beaks laced with their poisonous preen oil to produce small blistering wounds, the only difference in their case being the hooked tip of the bill administers the toxin instead of tooth-like beak serrations. As they administer their poison into the bloodstream of their enemies, the vulturine flareakeet along with the fanged firefinch would be considered rare examples of venomous birds.
But the vulturine flareakeet takes this one step further. Mowerbirds including firefinches continue to demonstrate surprising dietary plasticity, or the ability to eat a wide variety of foods, which gives them a competitive edge over specialized competitors. Like the bloodybill firefinch, this species also includes meat in its diet, though it does not target other firefinches specifically. Occasionally at all times it will catch a smaller bird, murd, or other such hapless animal and envenomate it. During the breeding season however, such vertebrate prey becomes over 90% of its diet, and virtually all its nestlings are fed until they fledge their nests. Taking advantage of their stored terpenoid chemicals, they use them offensively rather than defensively. Being bigger than many firefinches and living in the jungle, where their primary aerial predators are less common, they can afford to reduce their own toxicity in order to quickly and effectively kill prey to feed their young. By gathering their preen oil onto their jaws, then biting and killing other birds and similar prey, the adult can bring home a far larger kill than it would by individually collecting small insects it would be limited to without its venomous bite, and its young can grow larger and healthier at a quicker rate. Now, the featherless head of the adult comes in handy as it dismembers carcasses, parting out the meat to its hungry nestlings.
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The artillery finch is a member of a third firefinch genus which represents a sister group to all other species. Their plumage is among the most divergent of any firefinch, predominately made up of black and white bands with bright red wings and erectile orange feathers on the rump. The tail is very long and has three wire-like feathers which angle foreward when the tail is lifted. Ground-living, poor-flying birds with long legs, they are fast and nimble runners which make their home in thick stands of blistergrass, which makes up virtually their entire diet. Running along worn paths through thick cover, they are high strung and jumpy, but not for fear of predators, but rather of rivals. These firefinches are extremely territorial, and though they live in small related flocks of their own kind, they have no tolerance for other firefinches invading the groves of meadowspark and other flameflowers in which they live. Their hostility may be related to the temporary lifespan of blistergrass thickets as they are eventually shaded out by trees through the process of ecological succession. The level of aggression that the artillery finch exhibits is correlated to the age of the thicket in which they live, and as their territory shrinks over time, they become extremely possessive of it, and will challenge any rivals - either unfamiliar members of their own species or other species - which dare invade it. In doing so, they protect their food supply as it becomes more limited, increasing how long it can remain habitable to them.
Their chicks are raised in grass nests beneath the foliage of blistergrasses, which provide a good degree of protection from predators. These firefinches do not feed their young a different diet than the adults take, which means the chicks grow much more slowly on flameflower meals than related species do on insects or meat, but also that their chicks will be poisonous from infancy. This prolonged period of dependence may nonetheless contribute to the aggression of the adults in defending their territories from rivals, as other firefinches will not be discouraged by their toxins. It has certainly contributed to another defensive behavior exhibited by these firefinches toward other types of enemies.
This genus of firefinch can throw sticky beads of their cantharidin-laced preen oil long distances by flicking their tail feathers, and do so when their young and especially their eggs, which are completely non-toxic, are threatened by other animals, including larger ones that do not mean to eat them, but could simply step on them. To eject their chemicals is energetically costly, though, and so these birds demonstrate an elaborate warning display before they will begin "shooting", in which they raise their tails high in the air and jump furiously up and down while hissing and snapping their beaks. If pressed, the flock will resort to flicking blistering droplets of oil into their predator's eyes and mouth for a distance of up to 5 feet, a deterrence to almost anything which might want to eat their babies. Only other mowerbirds, namely the bloodybill, are immune to such an attack, but the artillery finch is a versatile fighter, and has a back up plan for facing firefinch rivals. Artillery finches are equally competent at hand to hand combat, and have evolved a large spur on each ankle which they use to attack one another and other firefinches, seeking to wound them and occasionally killing them in aggressive mobs. Their habit of running along the ground and disappearing into cover makes them hard to fend off and lets them ambush flocks of rivals, jumping out suddenly and surrounding their enemies. As they are hard to follow in their system of narrow hidden trails and pathways, bloodybill firefinches that try to access their nests are apt to be cornered and killed one by one by the small but formidable residents before ever reaching the vulnerable chicks.