Brazilian (bird) beauties

We saw more than 275 bird species on our excursion to the Pantanal and Cerrado of Brazil, and they are all beautiful in their element, but of course some — are just a little more beautiful.  Here are my top 12 Brazilian (bird) beauties, not necessarily in any order.

Toco Toucan, one of the signature birds of the region. (Photo by Debbie Reynolds*)

This may not be the most photogenic shot of the Cocoi Heron, but the scene was beautiful.

The Chestnut-eared Araçari, a bird of many colors, is most closely related to Toucans.

Brazil is full of Hummingbirds, and the Glittering-throated Emerald is one of the beauties.

Peach-fronted Parakeets are just one of the many handsome species of parakeets in Brazil.

An Agami Heron in all its iridescent teal and purple splendor.  This is the bird that people ask about… “did you see the Agami Heron?”

Striking blue and gold colors make the aptly named Blue and Yellow Macaw a standout.  They are rather noisy though.

Tiny, but beautiful, the American Pygmy Kingfisher in green and chestnut brown colors is the smallest kingfisher in the Americas.

Male Band-tailed Manakins are striking in red and gold, with a distinctive white eye.

We only saw the Blue-headed Trogon once and from far away, but it really stood out in the dark leaves.

Rufous-tailed Jacamars look like they might be related to hummingbirds, but they are more closely related to woodpeckers.

Of all the birds we saw, the Sunbittern might be the most unusual and striking.  It really deserves its own blog post…(Photo by Debbie Reynolds*)

(*Fellow travel and bird photographer enthusiast, Debbie Reynolds, often takes better photos than I do, so I asked her to contribute to this post.)

Now here’s an amazing (coevolutionary) story…

Yellow-rumped Caciques (members of the blackbird family) enjoy a love-hate relationship with Giant Cowbirds in the Pantanal of southern Brazil.

The players in this story:

Yellow-rumped Cacique

A couple of Yellow-rumped Caciques near their woven nest, in a Cacique apartment house.  Caciques are highly social birds and nest together in high density, each individual female weaving multiple nests (to confuse the predators) in close proximity to her neighbors.  Males help defend the nests from intruders, but they are too busy attracting more females to their apartment house to help with the nest building.

The multiple, hanging, woven nests of the Yellow-rumped Cacique form a huge complex in tall trees in the Pantanal of Brazil.  There may be as many as 200 nest structures in one large “apartment house”.  Note the presence of a wasp nest in the middle of the image — looking like a gray loaf of bread.

Giant Cowbird

Giant Cowbirds, like other cowbirds, are obligate nest parasites, using many other (and smaller) bird species as hosts for their offspring. Female Cowbirds furtively explore potential nests when owners are absent, and then quickly lay an egg and leave. The chick is usually larger than the host chick and grows more quickly, outcompeting the host chick for food delivered by the female.

Well, it’s not exactly love between Caciques and Cowbirds, but the Caciques exhibit a great degree of tolerance for the presence of female Cowbirds who deposit an egg in Cacique nests, forcing the single mothers to raise their {adopted} large, greedy chicks along with their own.  BUT the benefit of this relationship is that the Cowbird chicks have a great fondness for botfly larvae that are ever-present in bird nests, and will pick them off themselves and the Cacique chicks as well, for a little extra nourishment.  In the end, Cacique nests with high degrees of botfly parasitism and Cowbird chicks in the nest actually fledged more offspring.

Yellow-rumped Caciques only lay two eggs in their long, hanging nest, but usually are only able to fledge one chick.  Between botfly parasitism and nest predation by larger birds or monkeys, there is low fledging success in this species in much of its range.

But that’s not the end of the story.  There is another player:  Polistine wasps, medium-sized wasps related to yellow jackets that build a large, papery nest, are aggressive hunters of flying insects, like botflies.

Caciques seek out trees with wasp nests, leaving a respectful distance between their nests and the wasp nest to avoid arousing the insects.  Wasp arousal, however, IS triggered by monkeys and larger-bodied chick predators like Toucans, Caracaras, or Great Black Hawks that move the branches and nests in their search, and most often, the predators are driven away by the wasps.

Yellow-rumped Caciques aren’t always so lax in allowing Giant Cowbird females access to their nest.  In fact, if the nest apartment house is built near a wasp nest, the wasps act like botfly exterminators, and with less risk of botfly larvae debilitating their chicks, the Caciques actively defend their nests against Giant Cowbirds.  The wasps have also been observed to drive away monkeys who try to raid the Cacique nests. So, there is a double benefit of nesting near wasps.

And there is still more to the story.

Yellow-rumped Caciques also seek out big trees on islands in their riparian habitat to build their apartment houses, because Caimans or Giant Otters in the rivers will attack and eat anything that tries to cross the river onto the island, such as snakes that are adept at climbing trees with an appetite for chicks.  In these situations, Caciques will also be intolerant of Giant Cowbirds presence.  Female Caciques stay close to their apartment house, foraging individually rather than in a group, so that there are always large numbers of them present to mob predators and Cowbirds and drive them off.

Adolescent Yellow-rumped Cacique females may not breed until they are three years of age, but stand guard at the nest apartment house ready to drive away predators and Cowbirds.

An adaptable breeding strategy, coupled with their high degree of sociality for nest defense, helps the Yellow-rumped Cacique survive in a world full of predators and parasites.

Scenes from the Cerrado — Savanna raptors

Open savanna with nearby cropland should be a mecca for invertebrates and small herbivorous vertebrates and the raptors that feed on them.  The Brazilian Cerrado is home to at least six species of small mice and rats and four species of small marsupials, as well as a variety of snakes, lizards, small songbirds, and a host of small and large invertebrates that frequently show up in the diets of the local raptors: Roadside Hawks, Savanna Hawks, White-tailed Hawks, and Great Black Hawks, as well as the Aplomado Falcon, the Long-winged Harrier,  two species of Caracara, and the Burrowing Owls.

That seems like a LOT of different raptors all competing for the same sorts of prey in the Cerrado.  Our northern grasslands have far fewer raptor species patrolling them.  How do all these southern species coexist?

Roadside Hawks are the smallest of the hawks in the Cerrado, about 12-16 inches long and weighing about 8 oz.  They tend to eat more insects than the other hawks.

Savanna Hawks resemble Red-tailed Hawks in size, almost double the length of the Roadside Hawk, but weigh less than 1000 g (2 lb).  Their large wing area makes them well-suited to soar over the Cerrado on the lookout for small mammals, reptiles, or large insects.

White-tailed Hawks are stocky, heavy birds, roughly the same length as Savanna Hawks, but much heavier (up to 2.5 lb).  They are often seen near recently burned areas (like that above) where prey stand out against blackened soil or recently emerging grasses and forbs.  They tend to eat more small birds than the other hawks.

Great Black Hawks are the largest hawks in the Cerrado, measuring up to 25 inches in length and more than 2.5 lb in weight.  They dine on snakes, small mammals, and large insects, often hunted on foot in the Cerrado.

Aplomado Falcons are the size of a small Peregrine, and like other small falcons, hunt small birds in the grassy parts of the Cerrado.  They may follow Maned Wolves and attack the small songbirds the wolves scare up, but they may also feed heavily on insects flying around at dusk, catching and eating them while flying.

A rare sight, an Aplomado Falcon perched on a low shrub in the Cerrado.  These falcons have been observed to hunt cooperatively, with some individuals flushing the prey while others attack.

Caracaras are members of the falcon family and are strong flyers, but do not exhibit the aerial attack strategies of the true falcons.  Most Caracaras are ground feeders, scavenging left-overs, raiding the nests of ground-nesting birds, eating live insect or small vertebrate prey.

The Southern Crested Caracara is the largest member of the Falcon family, a stocky bird with long legs and a strong beak.

This juvenile bird, not quite as good-looking as the adult, is less than half the weight and about 1/3 the length of its larger cousin, the Crested Caracara. It too, is an omnivore, feeding on carrion, fruits, small invertebrates, and amphibian and reptiles it encounters on the ground.  It has also been called “tick bird” for its habit of picking insects off large mammals, like the capybaras.

Last in this long list of Cerrado raptorial predators is the little Burrowing Owl, which definitely gets the cuteness award.

Unlike most owls, Burrowing Owls are somewhat diurnal, extending their hunting into the evening hours.  Although they catch their prey on the ground, they usually hunt from a favorite perch — a bush, a tree, a fence post, or even a termite mound.

Less than a foot high, and weighing less than 1/2 pound, these diminutive hunters of the savanna look for small invertebrates, lizards, and small rodents moving about in the sparse grasses.

A pair of Burrowing Owls, near a nest cavity, taken over from armadillos. Rattlesnakes also prefer these holes, and the little owls have been known to hiss like a snake at a potential predator that comes near the nest entrance.

So many predators in this ecosystem, sustained by the variety of small mammals and marsupials, ground-nesting songbirds, lizards, snakes, toads, and a huge variety of invertebrate prey, all sustained in turn by the immense variety of Cerrado plant species, both annual and perennial, that turnover rapidly in this fire-maintained system.

the love life of the Greater Rhea

At least one species of large flightless (ratite) bird inhabits each of the major southern continents: the ostrich in Africa, the emu in Australia, and the Rhea in South America.  All probably followed a parallel evolutionary path of flightlessness and gigantism from their flighted ancestors, once their continents had broken away from the southern supercontinent of Gondwanaland during the Cretaceous period.

Evolution of flightless (ratite) birds, from MappingIgnorance.org

While traveling through the Cerrado of Brazil, we spotted Rheas many times, as they foraged in agricultural fields and grassy, open areas of the Cerrado.

Question: How do flightless birds get over a fence?

Answer: they go under it!

Rheas stand over 5 feet tall, supporting their elongated neck and football-shaped body on long legs.  They are not particularly attractive, with their loosely feathered plumage that usually looks disarrayed and scraggly.

Three large, wide-spaced toes and long, sturdy legs support this 80 pound, giant omnivorous bird.

They do have pretty brown eyes, though.

Rheas spend a lot of their time, head down, walking slowly through open grassland or crop fields hunting for tidbits of grain, grass, insects, perhaps small nestling birds, or anything else edible to pick up and toss back into their gullet.

During the non-breeding season, they may be shy, and run from perceived threats. This bird is moving at a fast trot, but Rheas can run almost 40 mph, using their outstretched wings as rudders to steer right and left.

Other than being large and flightless, Rheas seem mostly unremarkable.  But not when it comes to their love life.

Males engage in chest-bumping and neck thrashing to establish their nesting territory.

Two male Rheas are duking it out, pushing against each other breast to breast while beaking each other.

Once they have established who is top dog in a particular area, a male actively courts and copulates with a number of females.  Then he builds a nest by trampling and scraping out a grassy disk, pushing dirt away from the center until he has built up a mound three feet across and 30 inches deep and invites his courted harem of females to lay their eggs within.  Before he begins incubating his clutch of eggs, there may be somewhere between a dozen to 50 eggs in his nest mound.  Incubation takes about a month, and the eggs hatch within hours of each other.  The chicks are protected by the male for up to six months.  So each male is making about a 7 month investment in his offspring.

Male Rhea and chicks (photo from https://www.animal.photos/bird4/rhea-gtr.htm)

Meanwhile, in a complete reversal of the usual female role in nurturing their offspring, the females have wandered off, looking for other, likely males with whom to mate, and deposit more of their eggs in another nest, leaving that male to incubate and rear their chicks.  They will have nothing further to do with the rearing of their chicks.

This complicated “romantic” breeding strategy has the fancy name polygynandric, which simply means males breed with more than one female (like Red-winged Blackbirds) and females breed with more than one male (like many shorebird species).

Footlose, and fancy free, a female Rhea, can just lay her eggs, and then walk off.

So, does this peculiar breeding strategy work?  As you might imagine, incubating such a large number of eggs might be disadvantageous, and in fact, only about 3/4 of such large clutches actually hatch.  Worse yet, territorial males sometimes give up incubating duties to another male so that they can go collect another harem at another nest site.  And 65% of the males were found to desert their nests in the middle of incubation, either because of disturbance from predators, livestock, or humans, or for no apparent reason.  In one study of 34 Rhea nests, only 20% hatched any chicks at all.

With this low reproductive success, Rheas in South America are a near-threatened species, especially with more of their Cerrado habitat being converted to agriculture.

Scenes from the Cerrado – plants and their pollinators

Although we visited the Cerrado in the dry season, there were many shrubs and trees putting out new leaves and flowers, even in the absence of any trace of rainfall for the past 6 months.  Extensive underground aquifers that fill during the rainy season are tapped by deep roots of most of these plants, ensuring that they can flower and produce seeds when their pollinators and seed dispersers are present.

One of these small shrub/trees was quite common, and was particularly noticeable because of its huge displays of large, white flowers.

This is the Pequi tree, (Caryocar brasiliense), whose large white flowers produce copious nectar and pollen.  It blooms only during the dry season — July to September.

The leaves of Pequi trees are leathery, an adaptation to living in an arid environment. The flowers are rather large (bee in the top flower provides size comparison) and white with lots of yellow stamens.  They produce copious nectar throughout the night, which is higher in sugar concentration in the morning than the evening.

Artistic view of the Pequi flowerhead

If there were a single plant species whose absence would markedly affect insect, bird, mammal, even human populations in the Cerrado, the Pequi would be it.

Pollination is done mainly by bats at night, but the plant is also visited by nocturnal moths, wasps, and ants, all feeding on the nectar produced by the flowers.  In the daytime, no nectar is produced, but bees and wasps visit the flowers to feed on pollen.

Hummingbirds may be found on the flowers at dusk and in early morning, cashing in on that last sweetened formula of nectar the flowers put out.  Guira, White-lined, Palm, and Siaca Tanagers along with Curl-crested Jays also frequent the flowers at dusk as well:

Colorful Guira Tanagers sip the nectar, eat the flowers, and munch on the seeds of the Pequi.  Photo by Dario Sanches.

Curl-crested Jays hang around the Pequi trees in the very early morning hours, perhaps to feast on the insects that are attracted to the flowers. (Photo by Debbie Reynolds)

Glittering bellied Emerald hummingbirds are one of many hummingbird species that depend heavily on the nectar provided by flowering trees.

But that’s not the only role that Pequi plays in the Cerrado.  Well-pollinated flowers produce a bounty of nuts, eaten by animals and especially favored by indigenous people of the Cerrado.

Pequi seeds in Cuiaba, Brazil market (Photo by Mateus Hidalgo).

The pulp surrounding the seeds has been described as aromatic, fruity, and cheesy, and can be eaten raw or used to flavor other dishes.  The seeds (with spines removed) are roasted and eaten like peanuts, or crushed to extract their oil, so the whole fruit has great commercial value.  Pequi trees are typically planted around villages for residents to harvest the tree’s bounty.

Scenes from the Cerrado of Brazil – part 1

So many memories of so much wildlife, gorgeous sunsets, and intriguing landscapes of the Cerrado of Brazil.  And so many stories…

Peach-fronted Parakeets and other members of the parrot family are primarily fruit and seed-eaters in Cerrado vegetation.  This was an amusing scene because the parrot on the left eventually stole the seed head that the parrot on the right was feeding on, as shown below.

Success! The other guy gets the seed head.

Several species of Parakeets are commonly found in the Cerrado, because in these diverse habitats with high plant species diversity, there are numerous sources of fruits and seeds for them to exploit. Peach-fronted Parakeets are common in the open landscapes of the Cerrado.  They spend much of their time on the ground, searching for fallen fruits, seeds, and even insects.  Their numbers (and reproductive success) are no doubt furthered by all the agriculture occurring in the Cerrado.  These parakeets, in particular, are voracious consumers of soybeans and corn, and are probably considered pests by Brazilian farmers.

Brazil’s giant savanna

You might be getting the impression from previous posts that everything in Brazil is “Giant”, and they do have the largest rainforest on earth and quite a few giant animals, but what is less well-known (and is disappearing even more rapidly than the Amazon rainforest) is the very large and most diverse savanna grassland on earth, the Cerrado of southern Brazil.

The Cerrado is the second largest biome in South America, after the Amazon rainforest, covering about 770,000 square miles, approximately 21% of all of Brazil.  The map highlights native and protected areas, but agriculture encroaches on that space more and more each year. (Map from Francisco et al. 2015. Natureza Consevaçao 13: 35-40.

The Cerrado is not just a vast grassland, but a collection of savanna, shrub, grass, mixed grass and shrub, dry forest, humid forest, riparian (stream side) habitats that give rise to the amazing species diversity of this area.

We got many opportunities to survey this habitat diversity (and the animals that live in these areas) on our games drives through Las Emas National Park, about 1000 km northwest of São Paulo.

Our Safari vehicle for cruising the backroads of Las Emas National Park.

Savanna habitat is largely grass with occasional trees.

Shrub habitat is comprised of low vegetation and short, woody shrubs and trees. Deer and human trails wind through the shrubland in places.

Grass habitat of the Cerrado, bordered by a fire road.  We had a nice sunset on our drive on this evening.

A Great (not Giant) Black Hawk perched on a low shrub for a view of its prey hidden in this mixed shrub-grassland, where there is less grass and more shrubs present.

This is a fire-maintained ecosystem, and we could see the transition from habitat type to habitat type, as areas recovered from periodic fires.

A firebreak, burned every year separates grassland from shrub land in the distance.

Dry forest is characterized by a lot of dry, crunchy leaves on the ground, but green leaves and flowers are budding out above. How do the trees manage this?

Humid, wet forest has small streams running through it, and is a welcome relief on hot, steamy days when temperatures are 10 degrees hotter in the savanna and shrub habitat just outside the forest. We were looking for the Pheasant Cuckoo here, which is a giant of the cuckoo family!

On our hike through the hot savanna, we came to a very clear, fast running stream bordered by gallery forest on both sides. That cool water looked very inviting on a hot day!

With this much habitat diversity, you can imagine how much diversity of life resides in this vast grass and shrub complex of the Cerrado.

Everything about the Cerrado is unique and surprising:

  • periods of torrential rain (2-6 FEET per year) followed by extensive drought (190 days and counting so far in 2019)
  • water storage in vast aquifers that are tapped by the deepest tree roots
  • unique vegetation (more than 10,000 species of plants), adapted to drought with more extensive biomass (root systems) below ground than above it
  • 837 bird species, about 30 of which are endemic (found no where else on earth)
  • 67 species of mammals, including the Giant Armadillo and Giant Anteater, as well as the Maned Wolf, found no where else in the world
  • 120 species of reptiles, 150 species of amphibians, and probably several million species of invertebrates, especially insects, still to be counted

But the Cerrado is a vast and flat land, perfect for cultivation, and so Brazilian farmers have converted much of it to agricultural production of soybeans, corn, cotton, and sugar cane. (Brazil is now the #1 exporter of soybeans, much to the dismay of U.S. farmers.)

The spread of agriculture and modern farming methods has cut back the native Cerrado habitats to 3% of their former land area. Photo from undark.org (“the slow death of ecology’s birthplace”)

Large expanses of crops have replaced the Cerrado vegetation.

Why do some birds have such long tails?

Aerodynamically speaking, tails are a drag for a bird that needs to gain lift to remain airborne, so tails should be short and flexible to act as rudders in flight.  Yet some birds (especially males) sport elongated, ornate, feathery ornaments at the ends of their bodies intended to attract the opposite sex.  These long tails are indeed an impediment to flight, but the birds’ ability to fly with such a handicap is a signal to the female of the male’s fitness as a mate.

In other species, both sexes have a forked tail with elongated outer tail feathers and shorter inner tail feathers —the most well known example being the Barn Swallow, a bird famous for its rapid changes of direction in flight as it pursues insects.  A number of other bird species exhibit similar tail structures, but you have to wonder how this sort of a tail helps aerial insect foragers?

Swallow-tailed Kites, named not only for their tail similarity to Barn Swallows, but also for their darting flight patterns as they pursue insects, can rapidly change direction, fly upside down or even backwards moving only the outer tail feathers as they glide on extended wings through the air.

While on hikes in the Pantanal in Brazil, we had an opportunity to watch Fork-tailed Flycatchers foraging from a favorite perch, as they sallied out and back in tight circles.

Fork-tailed Flycatcher sitting with its elongated tail streamers fluttering in the breeze.  These birds are commonly found foraging in open fields and riparian pastures, from Mexico to Argentina, and rarely wander up the east coast of the U.S. in migration.

Some rapid-fire photos of their predation attempts might help illustrate how elongate outer tail feathers are used to produce the quick direction changes in these aerial foragers. (Successive images of the bird’s flight have been super-imposed on the original image of the bird perching.)

From its perch, a Fork-tailed Flycatcher soars upward on a foraging attempt.

Is that curl in one outer tail feather purposeful or just a result of wind?

Super-imposed images of the Fork-tailed Flycatcher as it descends back to its perch.  The change in the flexion of the upper outer tail feather looks more purposeful.

So, how do these elongate outer tail feather assist in rapid direction changes in these birds?

In a study of the aerodynamics of flight in Barn Swallows, Åke Norberg noted that the outer tail feathers are drooped below the rest of the tail surface to increase lift and reduce drag in the tail. (This mechanical advantage is similar to the way flaps on the wing of fixed aircraft function to achieve lift.)  Norberg further demonstrated that the arc of the central shaft of the outer tail feather and its elongated streamer are adjusted continuously as the bird turns in tight circles, ascends, or descends. Alternate lift/drag differences on the two sides of the tail enable rapid changes in direction.  Thus, the longer the tail, the more efficient the flight in complex aerial patterns.

Presumably, the same advantages of tail structure and foraging habits hold for other long-tailed members of this large family of flycatchers (Tyrannidae), like the Scissor-tailed Flycatcher of the southwestern U.S. and the Streamer-tailed Tyrant of the Brazilian Pantanal.

Scissor-tailed Flycatcher

Streamer-tailed Tyrant

 

[R. Åke Norberg, 1994.  Swallow-tailed streamer is a mechanical device for self-deflection of tail leading edge, enhancing aerodynamic efficiency and flight manoeuverability.  Proceeding of the Royal Society B. Vol 257, 22 September 1994.]

Jabiru – a giant stork

The last in this series of the very large animals of South America is the Jabiru Stork, the tallest flying bird of the continent (equal to the flightless Rhea) with the second largest wingspan (after the Andean Condor).

Males are about 25% heavier (about 15 pounds) than females (about 11 pounds) and may reach 5 feet in height.  Their wingspan ranges from 7 to 9.5 feet across their body.

A stork with a wingspan so long it doesn’t even fit in the frame of the camera. (Photo by Debbie Reynolds)

These large-bodied wading birds feed near streams, ponds, or rivers, but are not at all picky eaters, taking whatever crosses their path: mollusks, amphibians, snakes, mice, small birds or bird eggs.  They probe with that enormous bill into mud for invertebrates which they can detect with the tip of the bill, grab, and throw it up and back into their gaping maw,

The bill is wide and thick and slightly upturned.  When they stand around in swampy water, they are likely to be besieged with biting flies that are attracted to the naked black skin of the stork’s head. (Photo by Debbie Reynolds)

Although usually seen in pairs, Jabirus respond to high densities of food (e.g. small mammal population explosion) by congregating there in large numbers.

Jabiru parents build an enormous stick nest which is used for multiple years, and may end up being 3 feet wide and 6 feet deep.

Their nests are easy to spot from far off. Usually one parent stands guard to protect the chicks from predation by raccoons or other storks.

They rear their 2 to 5 chicks to fledging for almost 4 months and then continue to feed their young for another 3 months.  Consequently, Jabirus usually breed every other year; only 25% of the pairs may be successful raising another clutch of chicks in a successive year.  But since they are long-lived birds (35 years), they will undoubtedly replace themselves many times over.

One parent shields the chicks from the heat of the afternoon sun. It’s amazing how much just a little shade lowers the heat load in this tropical environment.

Jabiru Storks are truly an iconic bird of tropical South America.