That Bird Blog – Bird Care and History for Pet Birds

 

I must admit to a certain affection for starlings…this in spite of the fact that the introduced European starling (Sturnus vulgaris) is a serious avian pest (note the Latin name!).  However, I have rehabilitated quite a few, and found them to be quite as intelligent as their better-loved cousin, the Indian hill myna.  I was also shocked at the speaking abilities of a starling maintained for years at the American Museum of Natural History – in marked contrast to his stuffed companions, this lively fellow spoke as well as most parrots!  But for pure beauty and personality, few can match the amethyst starling, Cinnyricinlus leucogaster.

Starlings in Zoos and Nature

Working at the Bronx Zoo put me in contact with several gorgeous starling species, including the amethyst, superb and glossy.  In a huge exhibit teeming with African birds of every description, it was a pair of amethysts that regularly stole the show with their brilliant colors and bold demeanors.

One of the most striking of the world’s 114 starling species, male amethysts are clad in a deep violet set off by a brilliant white breast.  In the sunlight, they are, like most starlings, as iridescent as any hummingbird (even the rather drab European starling is quite showy in its winter plumage).

Range and Habitat

Amethyst starlings range widely over much of Sub-Saharan Africa, from Senegal in the west to Tanzania in the east, and south to northern South Africa.  Inhabiting open woodlands, forest edges and river valleys, they are not uncommon, but, staying to the treetops, are less evident than other starlings (its hard not to be aware of most starlings!).

Breeding

Pairs form in the mating season, after which the birds separate into small flocks.  In contrast to those starlings that have been well-studied, amethyst flocks are usually composed of a single sex.

Diet

Amethyst starlings take a wide variety of food, including moths, katydids, spiders, snails and other invertebrates, tree frogs, lizards, carrion and a wide variety of fruits, buds and sprouts.  Like most starlings, they are not above pillaging the nests of other birds, taking both nestlings and chicks.

 

Further Reading

An interesting, in-depth survey of the wildlife inhabiting amethyst starling habitat in Cameroon is posted at http://www.ioe.ucla.edu/ctr/reports/Faunal.pdf.

Image referenced from Wikipedia and originally posted by LTShears

Please see Part I of this article for an overview of some tropical fish foods that may be fed to pet birds.

The protein requirements of finches are often over-looked by bird keepers, as these captivating little birds are usually thought of as “seed-eaters”.  However, nearly all species readily consume insects in the wild.  Invertebrate-based protein is also essential for bringing most into breeding condition, and for parents with chicks.  Lories, painted quail, shama thrushes, white-eyes, Pekin robins and many others also relish and need invertebrate foods.  A number of products originally formulated for captive reptiles contain shrimp, snails, flies, Gammarus and other foods that make healthful additions to the diets of many cage birds.

Snails, Shrimp and other Canned Invertebrates

Canned invertebrates such as shrimp, snails, grasshoppers, crickets and mealworms represent an important and little-utilized food source for pet birds.  Most birds prefer that the shrimp be left out to dry for awhile, but will eagerly take the other items straight from the can.

Gammarus

Gammarus, tiny crustaceans usually referred to as “fresh water shrimp”, are actually amphipods, not true shrimp. They have long used as an important protein source for cage birds of all types.  Originally collected in Southeast Asia and rather expensive by the time they arrived in the USA, local Gammarus species are now used in the trade here.

Repto Treat Gammarus Shrimp Supplement, comprised entirely of sun-dried Gammarus, is a useful way of providing your smaller birds with this nutritious but often-forgotten food item.

Dried Flies and Egg Food

Zoo Med Anole Food, which contains freeze dried, laboratory-raised flies, is readily accepted by most small finches and softbills.

Every old-time bird keeper knew how to prepare egg food, which was considered essential for bringing birds into breeding condition.  Nearly all the birds with which I have worked, from tiny finches to massive cassowaries, consumed it with gusto.  Cede Egg Food is a convenient means of supplying your birds with this is nutritious, high protein treat.

Further Reading

Please see my article on Breeding Finches  for further information on the role of invertebrate foods in promoting reproduction.

Please also check out my articles on individual bird species for specific information.  You can also subscribe to my RSS Feed at

http://feeds.feedburner.com/ThatAvianBlog.

 

Image referenced from Wikipedia and first published by NIMSoffice.

Research conducted at New York’s Cold Spring Harbor Laboratory (Nature: May, 2009) has, for the first time, illustrated the complex interplay of genetics, learning and social situation in the acquisition of birdsong.

Learning What Song to Sing

As is true for all birds studied, zebra finches (Taeniopygia guttata) raised in isolation from others of their kind fail to develop the song typically sung by the species.

It was therefore long believed that birds learned species-specific notes by listening to the calls of adults.  In fact, zebra finches that are raised by society finch foster parents sing the song of the society finch, not their own, once mature.

The Surprising Influence of Genes

In the Cold Spring Harbor experiment, finches raised in isolation developed odd songs that were not typical of their species, and this song was mimicked by their chicks.  However, after 4-5 generations, the typical (natural, wild-type) zebra finch song began to emerge, despite the fact that the birds had never heard this song.

The shocked scientists concluded that the song is stored within the genome, but that several generations must pass before it emerges spontaneously.  Under normal circumstances (i.e. where the chicks are raised with exposure to the adult song), learning interacts with genetics to assure that the song is acquired right away.

Future Research Objectives

Ornithologists are interested in discovering if the same process is at work in other species as well…perhaps even the complex and beautiful song of the nightingale is encoded in each male chick.

This research also is expected to have important implications in the study of human language development, and will hopefully lead to new advances in speech therapy.

Further Reading

The zebra finch is one of our most important laboratory animals, and the story of its entry into the pet trade has some surprising twists and turns.  Please see my article The Unknown Side of the Zebra Finch for further information.

A review of this species’ vital role as a laboratory subject is posted at

http://genome.wustl.edu/genome.cgi?GENOME=Taeniopygia%20guttata

 

NightingGale image referenced from Wikipedia and originally posted by Orchi.

Cage size has a direct impact on pet bird health and quality of life.  This fact is well-recognized by experienced aviculturists…zoos in the American Zoo Association must adhere to strict exhibit size requirements for all species they maintain.

Small Birds

Oddly, smaller birds sometimes fare worse than larger species.  Most people realize that large birds need large cages.  They often assume, however, that finches and budgerigars can get by in tiny cages because they are “small”.  But size is relative, and each bird’s particular lifestyle must be taken into consideration.

Actually, many of the tiniest finches are quite high strung and, having evolved in a world where even large spiders are potential predators, are stressed by limited quarters.  Also, because they do not climb about as do parrots, most cannot use “as much” of their cages as can parrots, and need comparatively larger living quarters.

Cage Size and Health

Providing your bird with a larger cage is one of the most important steps that you can take in ensuring its good health.  Although an expense in the short term, it usually pays off in terms of reduced health care costs.

It is important to bear in mind that “survival” does not indicate that a bird is healthy or enjoying an appropriate quality of life.  Unsuitable living conditions are a primary source of stress in captive birds.  Stress weakens the immune system, and can leave birds open to attack by microorganisms (i.e. Aspergillosus fungi) which are of little concern to properly-housed individuals.

Birds should be able to “stretch their wings” each day…ideally, their living quarters should be large enough to offer reasonable exercise opportunities.  You will need to think carefully when deciding upon a cage purchase or upgrade…unfortunately, birds usually offer little indication of their needs in this area.  And, no matter how smart your parrot is, he or she will not tell you that the cage is too small (but if it does, by all means let me know!)…so please write in with your questions.

Improving Life for Bird and Bird Owner

Larger cages allow our birds opportunities to explore and engage in natural behaviors.  It is easier for us to hide food, add a variety of bird toys  that encourage foraging behavior, alternate perches and otherwise improve their lives and add to our own pleasure in keeping them in our homes.

Training is also greatly simplified, as personalities usually improve when additional space is provided.  A bird stressed by tight quarters is nearly impossible to interact with.

Breeding

When it comes to reproduction, a comparatively large cage is a necessity for most species.  Often, a move to larger quarters will actually stimulate breeding activity.

One caution … sometimes increased space, and the possibility of establishing a territory, leads to aggression among birds that co-existed in close quarters.  I learned this when I gave a group of laughing jay thrushes access to larger quarters without monitoring the situation…two of the five were dead the next morning.  Please write in if you feel this may be a concern in your collection.

 

Further Reading

You can read about the effect of cage size on finch behavior at http://www3.sympatico.ca/davehansen/finbehav.html.

Pet keepers have long known that birds react to our own eyes, seeming to be very aware of when we are and are not looking at them.  Researchers at the University of Bristol have now confirmed that birds modify their behavior in accordance with observers’ eye movements (please see “Further Reading” below).

Vision is the most important of the senses for most bird species…the optic lobe of a bird’s brain, and the size of the eyes in relation to the head, are comparatively greater in birds than in mammals.  Today I’d like to pass along some interesting facts on avian eyes.

Location of the Eyes

The eyes of predatory birds such as eagles are set close together at the front of the head, allowing for binocular vision (both eyes focus on the same subject) as in people.

Birds that are hunted by other animals usually have eyes that are set well-off to the sides of the head.  This allows for a greater range of vision and helps them to spot danger.  The ring-necked dove’s field of vision is 300 degrees, and by a slight movement of the head reaches 360 degrees.

Focusing Vision

Birds focus their vision by muscular action which changes the shape of the lens and/or cornea.  The avian eye lens is softer than that of mammals, allowing for quicker focusing.

Visual clarity is also affected by the angle of light as it passes through the eye’s cornea (as well I know – my corneas are pointed, and I’m virtually blind without a covering lens to push them back into shape!).  Cornea angle changes allow penguins to see well under-water, and diving birds such as cormorants to switch quickly from water-based to air-based vision.

Color Vision and Acuity

Structures known as cones and rods affect acuity (clarity) and color vision.  Birds see objects located at the very edge of their field of vision quite clearly – we see only “glimpses” and must turn and focus.  Most see at least 3-4 colors, but more research is needed.

The retinas of some birds have depressed areas, known as foveas, which are supplied with extra cones, allowing for particularly acute vision.  Foveas enable hawks to assess speed and distance while swooping down on prey.  Kingfishers, which dive on fish from above, have two foveas in each eye – one for air acuity and one to help them see when submerged.

Rods are light sensitive, and are particularly abundant in the eyes of nightjars, owls and other nocturnal birds.

Pupils

The eye’s pupil regulates the amount of light that reaches the retina.  Birds change the size of their pupils with highly specialized muscles.  The pupils of bird eyes are thicker than those possessed by most mammals, allowing for greater light penetration and sharper vision.

The Third Eyelid

Birds possess a clear, third eyelid, or nictitating membrane.  This membrane prevents the cornea from drying out during flight and offers protection underwater.

Further Reading

Please see my article European Starlings can Determine When People are Watching  for some interesting research and a personal story about the visual powers of an owl that liked to feed people.