Wednesday, January 30, 2019

Vasa Parrot (Coracopsis vasa). All Birds Considered.

Inspired by David Attenborough’s book, The Life of Birds, is a monthly spin-off segment of my blog called “All Birds Considered”, which I hope will bring attention to some of the more unusual, and lesser known birds of our world.


The Life of Birds by David Attenborough (1998)
https://avianmusing.blogspot.com/

Species; Vasa Parrot (Coracopsis vasa)

Introduction; The vasa parrots (Coracopsis) are three species of parrot which are endemic to Madagascar and other islands in the western Indian Ocean. Some taxonomists place the genus in Mascarinus.

Vasa Parrot (Coracopsis vasa) 
Image Credit: Wikimedia Commons
https://avianmusing.blogspot.com/

Description; They are notable in the parrot world for their peculiar appearance, which includes extremely truncated bodies with long necks, black to grey feathers and a pink beak.

The skin of both female and male vasas turns yellow during the breeding season, and there is often feather loss. However, in females the feather loss can result in complete baldness. Another interesting feature of the females breeding physiology is when her feathers, which are usually black to grey, turn brown without a moult. This is caused by the redistribution of melanin, which is the pigment that makes the vasas' feathers black.


Vasa Parrot (Coracopsis vasa) 
Image Credit: James Williams (2007)
https://www.birdforum.net/opus/Greater_Vasa_Parrot
https://avianmusing.blogspot.com/

Voice; Squawks, various sounds.

Behavior; In addition to their appearance they possess aspects of their physiology that make them completely unique amongst parrots. Vasa chicks are known to hatch after only 18–20 days of incubation, which is highly irregular as parrots of the vasa size range tend to take up to 30 days to hatch.

The male vasas' cloaca is able to invert into a hemipenis, which becomes erect during mating – a feature unique to the genus. This phallus is associated with prolonged mating enforced by a copulatory tie. Baby vasas possess pads on their beaks which when stimulated prompt a strong feeding response. These pads disappear after only a few weeks however the feeding or 'weaning' reflex remains unusually strong well into adulthood.

Habitat; The greater vasa parrot (Coracopsis: C. vasa) can be found in dry deciduous forest habitat, while the lesser vasa (C. nigra) is common to humid forests.

Conservation and population; Least Concern (IUCN 3.1). BirdLife International 2018. Coracopsis vasa. The IUCN Red List of Threatened Species 2018: Trending downward.

Source:



The Ascent of Birds, John Reilly, Page 132, 2018.

Wikipedia

The Life of Birds by David Attenborough, 1998.

Wednesday, January 23, 2019

Messel Bird Fossil offers unique feather preservation, and more

Messel Pit fossils—plant and animal life from roughly 50 million years ago, formed during the early Eocene Epoch of the Paleogene Period.

In that time, the fossil record of modern birds greatly improves, both in number of specimens and their completeness, providing a crucial window into the evolution of today’s birds.

The Messel Pit in Germany was rightfully declared a UNESCO World Heritage Site in 1995, due to its significance in geological and scientific importance.

Before becoming a UNESCO World Heritage Site, brown coal and later oil shale was actively mined at the pit from 1859. Commercial oil shale mining ceased in 1971, with plans for a landfill shortly thereafter.

Those plans thankfully never came to fruition, allowing local interests to purchase and secure the site.

In the few years between the end of mining and 1974, when the state began preparing the site for garbage disposal, amateur collectors were allowed to collect fossils. The amateurs developed the "transfer technique" that enabled them to preserve the fine details of small fossils, the method still employed in preserving the fossils today (source: Wikipedia).

Messel Fossil Transfer Method
Image Property of; http://www.senckenberg.de/root/index.
https://avianmusing.blogspot.com/
As a former collector myself, I am fortunate enough to still own a couple of these beautifully preserved Messel birds.

Here I report on one those birds, a bird as of now, not previously described.

The specimen features an assortment of feather types, as well as a complete skull, wing bones and a possible partial sternum. 

Unidentified Messel Bird Fossil
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
To photograph the fossil, I employed both natural light and an LED Tracing Light Box. Photography equipment used included a Nikon Coolpix P900 camera and a Dino-Lite AM3111 0.3MP Digital Microscope.

In order to see finer details surrounding the skeleton, an LED Tracing Light Box was positioned under the fossil, illuminating the plumage before images were taken. 

Unidentified Messel Bird Fossil
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Plumage details.

Approximately six primaries are preserved near the skull, one with a certain asymmetric shape (narrower leading edge), indicating an aerodynamic function. The rachis on the flight feathers appear wide and stiff. 

Unidentified Messel Bird Fossil Wing
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
At the base of these primary feathers lies what looks to be loosely arranged covert feathers. Did these coverts help smooth airflow over the wings? 

Unidentified Messel Bird Fossil Wing Coverts
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Feathers surrounding the top of the skull and neck collar (ruff) give the impression of being covered by hair-like filoplumes. Directly behind the skull feathers (top of skull) is a single body contour feather with symmetrical vanes. Its rachis is very thin and pliable. 

Unidentified Messel Bird Fossil Crown Feathers and Contour Feather.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
The Messel bird fossil also reveals a couple of uncommon body feathers that might be described as a semiplume, while others have the appearance of longer hair-like filoplumes. 

Unidentified Messel Bird Fossil Semiplume Feather.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/ 
Unidentified Messel Bird Fossil Possible Filoplume Feather.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
One of the most intriguing, and oddly placed feathers on this fossil lies directly on top the wings flight feathers. The identification and original placement of this feather(s) still escapes me, however, what is truly curious is that it appears to preserve some sort of color pattern to it (black dots). 

Unidentified Messel Bird Fossil Feather with possible color pattern.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Strangest of all feather preservation on this unidentified bird are the solid tips to the ends of some of the primaries and secondaries. Are these wide tips extensions of the feather’s rachis (rachis dominated)? Or are they highly fused barbs like we see at the ends of Cedar Waxwings (Bombycilla cedrorum) feathers? What purpose would this type of feather have to this ancient bird? 

Unidentified Messel Bird Fossil feather tip
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Unidentified Messel Bird Fossil feather tip
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Unidentified Messel Bird Fossil feather tip
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Unidentified Messel Bird Fossil feather tip
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Unidentified Messel Bird Fossil feather tip
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/

Aside from the waxwing feather, I have not found any other modern analog to compare this feature to, nor has the fossil record provided a clue.  

Cedar Waxwing (Bombycilla cedorum) feather tips.
Image Property of: Nature.org
https://avianmusing.blogspot.com/
What about the incomplete skeleton?

A partial sternum is tentatively identified based on its general shape, and proximity to the articulated wing bones. 

Unidentified Messel Bird Fossil possible sternum.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
The wing bones measure as follows; humerus 30mm, ulna 35mm, radius 32mm, carpometacarpus 20mm, phalanges of digit II 10mm.

The carpometacarpus also features an alular phalanx, with a splint-like alular claw perhaps flipped on its side (see cropped photo below).

Unidentified Messel Bird Fossil alular phalanx with possible claw.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
The skull is complete and articulated with the mandible. The head appears slightly smaller relative to the accompanying bone sizes. Skull of this bird measures 40mm. The beak alone measures 17mm. 

Unidentified Messel Bird Fossil Skull
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Closer inspection of the beak with a Dino-lite microscope brought to light a distinctively hooked tip, classically seen in extant raptors. In addition to the hooked tip, the fossil beak also appears to possess a few possible sensory pits (Herbst corpuscles). 

Unidentified Messel Bird Fossil hooked beak.
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/

Potential recognized species.

My initial choice of reference was Gerald Mayr’s book, Avian Evolution; The Fossil Record of Birds and its Paleobiological Significance (2017). Mayr provides a comprehensive look at the interrelationships and origin of crown group birds.

After numerous side-by-side comparisons of skulls both online and in text, I felt pretty certain that my Messel bird placed somewhere within the Early Paleogene parrot-like birds, more specifically, close to the halcyornithid Cyrilavis colburnorum. 

Cyrilavis colburnorum.
Image from Ksepka, Clark and Grande (2011)
https://avianmusing.blogspot.com/
Cyrilavis, from the North American Green River Formation, boast a very similar looking skull to my fossil bird. Its measurements however were slightly larger, not only in skull and beak length, but in every other skeletal component available for comparison. These figures were obtained through the research paper; Stem Parrots (Aves, Halcyornithidae) from the Green River Formation and a Combined Phylogeny of Pan-Psittaciformes, (Ksepka, Clark and Grande 2011).

I returned back to Avian Evolution; The Fossil Record of Birds and its Paleobiological Significance, discovering further examples (fossil images) of early Psittacopasseres, including the messelasturids Tynskya, also from the Green River Formation, and Messelastur from the same Messel fossil site. 

Skeletons of early Eocene representatives of Psittacopasseres.
Image from Avian Evolution; Gerald Mayr; 2017
https://avianmusing.blogspot.com/
Messelastur (according to Mayr) retained some key features, as opposed to other Psittacopasseres, which involved a very deep lower jaw and raptor-like pedal claws. The lower jaw of my Messel fossil appears deeper than Cyrilavis, but in no way would I have the expertise to claim “very much deeper”.

Mayr goes on to state that these similarities to raptorial birds are of particular interest because analyses of molecular data either identified falcons as the closest extant relatives of Psittacopasseres or supported a sister group relationship between parrots and owls.

Does the shorter, hook-tipped, raptor-like bill of my fossil indicate another trait of a messelaturid?

To be clear, my personal analysis of this Messel bird fossil has in no way scientific credibility behind it. This was conducted out of pure joy and respect for the fossil. My identification of feather types, bones, sensory pits, bill morphology and actual species may be completely wrong. Your thoughts and opinions are just as important, and may differ from my own.

Let’s continue to enjoy this remarkable bird by visualizing a setting which places this hypothetical carnivorous parrot on the ground, searching for invertebrates or small rodents. Its cursorial habits naturally select stiff feather tips to help protect the flight feathers during ground foraging, but are also co-opted for use in startling prey.

A prey item scampers to the underbrush, but is closely pursued by this low-flying predatory bird. Frustrated, the bird pokes its protected feathered head into the leaf litter hoping to sense movement.

The prey item bolts, but is grabbed by this bird’s raptor-like pedal claws, and quickly dispatched with its hook-tipped bill.      

Sunday, January 13, 2019

Avian Lumbar Interface; function and performance during air turbulance.

As winter weather goes, this year has been an easy one here in the Northeast United States. Temperatures and precipitation are well above average, with steady breezes throughout.

Conditions have not only been a blessing for overwintering birds, but also for winter flying insects like moths and crane flies.

This was quite apparent the other evening, when I inadvertently left on the lights on my front porch. Curious, I took a step outside to have a closer look, and was surprised to see how many insects were attracted to the brightness and heat of the glowing bulbs.

I went to sleep that night not knowing that I would soon awake to the sounds of strong gusts and heavy rain.

What I discovered the next morning was totally unexpected, and a bit troubling. Plastered against the side of my home were thousands of lifeless creatures. I thought; was this the perfect storm? Did all the insects in flight die that evening? Were these living things caught off guard by this type of sudden, violent weather?
  
Bruce Spanworm (Operophtera bruceata) windswept death
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
How about the birds? Except for owls, most were fortunately still at nighttime roosts. Yes, birds are affected by strong windstorms, especially hurricanes, which can sometimes displace them hundreds if not thousands of miles out of their normal range.

But does strong wind actually harm birds? I’m mainly referring to the shortest and most forceful of wind bursts. How do birds cope? Luckily, most have the cognitive ability to hunker down in thickets and shrubs, evergreen forests, or even settle on open water.

This particular event had me thinking back to a passage I recently read in the book, The Inner Bird; Anatomy and Evolution, by Gary W. Kaiser (2007). Here, Kaiser writes about some of the effects air turbulence has on the avian skeleton;

[There is some evidence that the interface between the thoracic and sacral vertebrae may be the Achilles heel of avian design. Most forest birds spend their entire lives in areas protected from strong winds, and the transition between the anterior and posterior regions of the spine is gradual and unspecialized. Flocks of songbirds, however, are often attracted to roadside salt and are killed when air turbulence from passing semi-trailers whips them into the air. Violent movements twist the body, concentrating stress at the relatively small section of the backbone between the two locomotory modules until it gives way. The casualties typically show massive internal bleeding near the lumbar joint, where the dislocated backbone has ruptured the blood vessels near the kidneys. Birds that live in open areas are often exposed to strong winds and may be vigorous fliers. Their lumbar areas often have some form of structural reinforcement.]

One has to imagine that many of our small long-distant migrants are also susceptible to air turbulence on their marathon journeys to and from their breeding grounds.    

The Blackpoll Warbler (Setophaga striata) for instance nests in the boreal spruce forests of Canada, while spending their winters in South America. To accomplish this, Blackpolls embark on a non-stop flight over the Atlantic Ocean, taking advantage of northwest tailwinds, following the passage of a cold front. Blackpolls migrate primarily at night when the atmosphere is more stable, making it easier to maintain a steady course. 

Blackpoll Warbler (Setophaga striata)
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
But there are risks to this behavior, even if the warbler has evolved the ability over millions of years to achieve this feat. In todays world, climate change has proven to be a major cause in shifts of weather and wind patterns.

Could a migrant Blackpolls body (12g) structure handle repeated variations in these newfound weather patterns?  Will their future now be “tossed on the sea of difficulty and uncertainty”?

How about the transitional fossil Archaeopteryx lithographica? What evolutionary structures did Archaeopteryx evolve to strengthen itself during its transition to powered flight? 

Archaeopteryx lithographica
Image Credit: Wikipedia
https://avianmusing.blogspot.com/
Much has been written about the conditions of life and of the environment in which Archaeopteryx lived.

Peter Wellnhofer, the world’s authority on the celebrated 150 million-year-old bird, describes in his excellent book, Archaeopteryx; The Icon of Evolution (2009), what the environment was like according to the fossil record;

[The terrestrial environment during Solnhofen times was a dry and warm region with sparse vegetation. At least occasional rain produced temporary rivers, freshwater lakes or small ponds to explain the existence of the fauna and flora we have recorded as fossils. It is likely that the Archaeopteryx individuals were blown out over the lagoons in flight from their habitat on land and pushed down by heavy winds or storms and drowned. Today, actively flying birds can be blown by strong winds over long distances. Keeping in mind that all Archaeopteryx specimens preserved as fossils in the Solnhofen limestone appear to have been young or immature individuals and weak fliers, this scenario can easily be imagined. Even such a catastrophe was a rare, quite exceptional and unusual event, as the scarcity of the finds demonstrates. Most of the Archaeopteryx skeletons are rather complete suggesting that they had been floating in the water for not very long period of time prior to deposition and burial. Since the Urvogels seem to have drowned and their lungs filled with water quickly, they sank to the bottom faster than if they had died on land, dried up and became mummified].  

Solnhofen lagoons restored
Image from: Archaeopteryx; The Icon of Evolution by Peter Wellnhofer
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Gary W. Kaiser does a nice job explaining the actual function of the lumbar interface;

[Because the front half of a bird’s body may be moving in one direction while the rear half tries to move in another, the lumbar interface must be able to cope with angular forces that try to bend or twist the spine. The vertebrate on either side of the lumbar interface are usually the largest in the body. Tall processes on top, or long hypapophyses below, restrain dorsoventral bending, and connections between adjacent processes limit rotation of the joint. Long lateral spines prevent excessive sideways bending]. 

Avian Lumbar Interface
The Inner Bird, Anatomy and Evolution. By Gary W. Kaiser (2007)
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Avian Lumbar Interface
The Inner Bird, Anatomy and Evolution. By Gary W. Kaiser (2007)
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
According to Wellnhofer’s reconstruction of the Munich specimen, Archaeopteryx’s thoracic vertebrae lacks both the tall, slender shape that prevents bending dorsoventrally, and hypapophyses for the attachment of ligaments which would have reduced twisting. Also, Archaeopteryx did not have a co-ossified synsacrum as in modern birds. 

Archaeopteryx thoracic vertebrae, lumbar interface and synsacrum
From Archaeopteryx, The Icon of Evolution. By Peter Wellnhofer (2009)
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/
Even if we could envision just one significant wind event per year (or decade), an Archaeopteryx (or a population of them) living in a rather flat, barren Solnhofen environment, would be in serious trouble.

Wellnhofer again writes; “even such a catastrophe was a rare, quite exceptional and unusual event, as the scarcity of the Archaeopteryx finds demonstrates”.

On the flip side of this thinking, maybe their scarcity is due to the exceptional events themselves. Who knows?

Twenty-nine species of Pterosaurs have also been found in the Solnhofen limestone, perhaps as a result of surprise wind storms (source: Wikipedia).

Interestingly, Archaeopteryx’s thoracic vertebrate, lumbar interface and lack of co-ossified synsacrum may speak as loudly about its behavior, as it does for its incredibly feathered body.

Ancient windstorm as depicted by Zdenek Burian
Photo Credit: Paul Cianfaglione
https://avianmusing.blogspot.com/