That Bird Blog – Bird Care and History for Pet Birds

People who breed canaries, shama thrushes and other noted songsters often comment that housing males within hearing distance of one another improves the quality of their songs. This theory has now been validated by researchers studying song sparrows (Melospiza melodia) at the University of Miami.

Typical and Improved Songs

It seems that male song sparrows stick to their “usual” repertoire under normal circumstances – i.e. when calling to announce the ownership of their territory. However, when challenged by intruding males, song sparrows dramatically improve the quality of their songs, selecting note ranges and song speeds that are difficult to perform.

Whether this is to convince a female or male (or both) of the singer’s vigor has not yet been established, but clearly the birds are physically changing their songs in response to a hostile situation. This finding contradicts the long-held assumption that, once acquired, male birds’ song patterns are largely static.

Practical Applications

The song sparrow findings may eventually shed light on the acquisition of language in people, as similar brain pathways seem involved. Those of you who keep groups of canaries, green singing finches or other songbirds may wish to experiment a bit as well, to see if some competition spurs your pets to new musical heights.

Thoughts on the Song Sparrow

As for myself, the first time I hear a song sparrow call (whether the song is “improved” or not!) each late winter is a thrill, assuring me that warmer days are not far off. In years past, I heard these little fellows only near salt marshes, but am happy to report that they have now expanded into suburban yards and city parks in and near NYC.

Further Reading

You can hear a song sparrow’s call and read related field observations at

http://www.sitkanature.org/wordpress/2007/03/15/singing-song-sparrow/.

Please also see my article The Role of Learning and Instinct in Bird Song for more information on this and related topics.

Image referenced from Wikipedia and originally posted by Factumquintus

Toucan bills are perhaps the best known of all bird appendages. Comprising 40% or more of the toucan’s total surface area, these long, colorful structures were thought to serve primarily as fruit gathering tools and, perhaps, to attract mates. However, research involving the toco toucan (Ramphastos toco), which sports the largest bill of all, has yielded some surprising new information.

Controlling Body Temperature

According to an article published in the journal Science (July, 2009), the toucan’s generously proportioned bill helps to keep its owner cool during hot weather. As temperatures rise, blood flows to a network of vessels positioned between the bill’s bony inner core and its hard outer covering (the rampotheca), where it sheds heat before circulating back into the bird’s body. Toucans are even able to precisely control the rate of blood flow to the bill.

A number of structures in other animals, i.e. elephants’ ears and crocodilian tongues, serve a similar function, although they appear less effective than toucan bills at shedding heat. It is theorized that the huge spikes on the backs of certain dinosaurs were the animal world’s first heat-dumping structures.

Toucans as Pets

Toucans make affection and interesting pets for those with the room to properly accommodate them (please see articles below).

Although their bills appear unwieldy, several toucans that I have kept were very adept at catching grapes tossed at high speed, and they rarely missed when aiming at the anoles (small lizards) that had arrived in their exhibit along with imported plants and trees.

Further Reading

Please check out my articles Introducing the Collared Aracari and Popular Zoo and Pet Birds: Toucans for information on keeping toucans in captivity.

Image referenced from Wikipedia and originally posted by Muchness

With a total population numbering 295 birds, only 60 of which live in the wild, the Puerto Rican Amazon (Amazona vittata) holds the unenviable title of one of the world’s 10 most endangered birds. A subspecies, A. v. gracilipes, once found on neighboring Culebra, Mona and Vieques Islands, is now extinct.

US Native Parrots

The Puerto Rican Amazon is the only parrot native to a US territory; it is also distinguished by quite possibly being the bird that helped lead Columbus to land on his first voyage (please see article below).

The sole Psittacine living on the US mainland is the endangered thick billed-parrot (Rhynchopsitta pachyrhyncha). Our only other native parrot, the Carolina parakeet, was hunted to extinction by the early 1900’s.

People unaware of this species plight are sometimes confused by all the concern…after all, parrots abound throughout Puerto Rico. However, these pet trade escapees are introduced species, which actually worsen the Puerto Rican Amazon’s plight by competing for food and nest sites, and, possibly, through hybridization.

Rats and other Threats

The Puerto Rican Amazon’s decline is largely due to deforestation. It nests only in pre-existing holes in tall, mature trees. When these trees are cut, the parrots cannot nest, or they use sites that are vulnerable to predators, competitors and hurricanes.

The introduced black rat (Rattus rattus) has also contributed significantly to this parrot’s problems. Alternately called the roof rat, this highly arboreal rodent takes eggs and chicks from 4 of every 6 nests in some areas. The pearly-eyed thrasher (Magarops fuscata) a small bird not usually known as a “trouble-maker”, has exploded in numbers in recent times (possibly due to changes in land use). Oddly, it now preys upon parrot eggs, and competes for nest sites.

In addition to the introduced parrots mentioned earlier, the island’s 3 large hawks pose a threat to the already depleted Puerto Rican Amazon population. Added to this is the species’ need for an intact habitat that supports varied food sources…it has been documented as feeding upon over 50 types of plants.

Recovery Efforts

Recovery efforts were initiated in 1973, at which time a mere 13 birds remained in the wild. Today, the US Fish and Wildlife Service administers the Puerto Rican Parrot Recovery Program, which encompasses both wild and captive management techniques (double-clutching, nest rehabilitation, predator control, releases, education).

Two wild populations have been established. That at Rio Abajo is comprised entirely of captive-bred birds, while the Loquillo National Forest (El Yunque) in Eastern Puerto Rico is home to both wild and released individuals. Before releases were initiated, detailed studies of the Hispaniolan parrot (Amazona ventralis) were conducted in the Dominican Republic and used as a template for the Puerto Rican Amazon’s return to the wild.

So far, ornithologists are cautiously optimistic. Released birds have been observed to associate with wild parrots, and radio tracking studies indicate that 40-50% of the captive-bred individuals survive the critical first 6-9 months. However, a dearth of suitable habitat and predation remain serious concerns.

A Lesson

The fact that an intense, well-financed, 36 year-long recovery program has only bolstered this species’ numbers to 295 illustrates well the depth of commitment needed if endangered animals are to be spared extinction. Rarely if ever is the mere establishment of a protected area sufficient.

Further Reading

Please see my articles Did Parrots Help Columbus Find America? and The Thick Billed Parrot for further information on Puerto Rican Amazons and US native parrots.

Rattus rattus image referenced from Wikipedia and orignally posted by Liftarn

Attention to breeding birds in public and private collections, along with increased legal protection, has helped a great many species to recover from earlier population crashes. In some instances, rescue efforts represent the only hope for a species, as none survive in the wild. However, upon reviewing species status reports recently, I was dismayed to see that bad as opposed to good news prevailed. From well known pet trade parrots to recently described Asian swallows, wild birds everywhere face grave threats.

Following is a summary of recent trends:

Frightening Statistics

Of the world’s 9,685 described bird species, 1,227, or 12.4%, are included on the IUCN’s Red List as threatened with extinction. Of these, 192 species are considered to be critically endangered, and likely to become extinct in the near future. An additional 838 bird species are classified as “near threatened”.

Since the year 1500, 133 species of birds have become extinct. Currently, 4 species exist only in captivity, and 15 species have not been observed despite surveys and may be extinct as well.

Since the year 2000, at least I species, Hawaii’s po’ouli, has become extinct and at least 2 species – Spix’s macaw and the Hawaiian crow – have become extinct in the wild.

Regions and Habitats of Concern

Indo-Malayan birds, Asian vultures and albatrosses face particularly hard times, with many species in severe decline.

Brazil and Indonesia lead the world in the numbers of resident threatened species, with 123 and 114 respectively.

Eighty seven percent of all threatened birds reside in forests. Tropical and subtropical lowland forests support 43% of all such species; 36% reside in moist montane forests.

The Most Significant Threats

Converting land to agricultural use is seen as the most critical threat to bird life, with 73% of all species being significantly affected. Logging and trapping/hunting impact 71% of all birds and, along with agriculture, are the main reasons behind the decline of 95% of threatened species worldwide.

Introduced species of birds, mammals, invertebrates, reptiles and plants significantly affect one third of the world’s threatened bird species via predation, competition, habitat alteration or the spreading of disease.

Further Reading

You can read more about bird declines, the effect they may have and what can be done to help at http://www.biodiversityinfo.org/sowb/section.php?r=introduction.

Researchers at Auckland and Oxford Universities have recently (August, 2009) published reports that may establish the New Caledonian crow, Corvus moneduloides, as the world’s most intelligent non-human animal.  Related to the familiar North American crow and raven (very bright birds in their own right…please see photo), New Caledonian crows have exhibited tool-using abilities that exceed those of even the most accomplished chimpanzees, orangutans and gorillas.

Birds with Reasoning Abilities?

In the Oxford University experiment, 5 New Caledonian crows were presented with a series of tools, some of which were out of reach, and an unreachable food item.  All five crows figured out the dilemma in sort order – four on the very first try.

The crows used the short, available tool to reach a longer tool, which was then used to hook and retrieve a still longer implement.  Equipped with the longest tool, the birds then pulled the food within reach.  Amazingly, none of the crows exhibited random experimentation – rather, each unerringly chose the proper tool to accomplish each part of the task at hand!

Never before has an animal demonstrated such a sophisticated degree of sequential tool use.  In fact, the crows, none of which had prior training, surpassed even what has been accomplished by well-trained primates faced with similar problems.  Scientists are now trying to determine if “analytical abilities” are involved (seems so to me!).

Gorillas and Parrots

I’m very impressed by the crows, but must also admit being floored by the cunning of a baby gorilla I cared for at the Bronx Zoo.  I was sitting with the animal all night to prevent her from pulling out an IV line attached to her arm.  She very definitely feigned sleep and then slowly inched her hand towards the IV line when I looked away.  Each time I turned towards her, she went “back to sleep”!
Of course we all have our parrot stories…please write in with some that might compete with these crows!

Further Reading

Please check out this amazing video of a New Caledonian crow in action at Auckland University.
 

One of the crows involved, known to researchers as “Betty”, has made animal behavior headlines in the past.  To read about her tool-making abilities (in this case, bending a wire into a useful hook), please check out the following National Geographic article: http://news.nationalgeographic.com/news/2002/08/0808_020808_crow.html.