"Cognitive biologists have revealed that ravens do understand and keep track of the rank relations between other ravens. Such an ability has been known only from primates. Like many social mammals, ravens form different types of social relationships — they may be friends, kin, or partners and they also form strict dominance relations. From a cognitive perspective, understanding one’s own relationships to others is a key ability in daily social life ("knowing who is nice or not"). Yet, also understanding the relationships group members have with each other sets the stage for "political" maneuvers ("knowing who might support whom"). "
ScienceDaily (Nov. 8, 2012) — It’s always a good idea to listen to your mother, but that goes double for baby fairy-wrens even before they are hatched.
If those fairy-wren babies want to be fed, they need to have a password — a single unique note — taught to them by their mothers from outside the egg. The nestlings incorporate that password right into their begging calls, according to researchers who report their discovery online on Nov. 8 in Current Biology, a Cell Press publication.
This remarkable example of prenatal learning is an adaptation that apparently allows fairy-wren parents to discriminate between their own babies and those of parasitic cuckoos who have invaded their nests. Females also teach their mate and any helpers the password by singing it to them in a “solicitation song” performed away from the nest. (via Fairy-wren babies need password for food)
Free-living pigeons are so ubiquitous they often go unnoticed, yet the species is remarkably diverse. The 350-plus breeds display traits ranging from curly feathers to stumpy beaks. But similar-looking pigeons aren’t necessarily closely related, reveals a study of 70 domestic breeds and two free-living populations. For instance, both English trumpeters and English pouters have feathers, not scales, on their feet, but they aren’t genetically similar. Conversely, two owl pigeons, the short-beaked African and the Old German, are closely related (though the former has a plain head while the latter sports an impressive crest). Investigating the genetic origins of pigeon diversity could help shed light on how similar traits—vital for survival and reproduction—have evolved in wild birds. (via Audubon Magazine)
Migratory birds are superbly adapted to store and use fat. Throughout their lives they repeatedly become morbidly obese, exercise at levels that far surpass elite athletes, and then cure themselves. Thus, they offer an intriguing model for study of lipid metabolism, exercise, and obesity.
30 years ago, efforts began to save the California condor, an iconic species on the brink of extinction. Since then, a lot of progress has been made, and the last count revealed 405 known California condors. The population is split between 179 individuals living in zoos, and 226 living in the wild. But while the progress that has been made so far is encouraging, it’s too early to say that the California condor has been saved.
Key among issues are lead poisoning caused by condors eating animals, or gut piles from animals, shot with lead ammunition.
ScienceDaily (May 14, 2012) — A male robin will be more diligent in caring for its young if the eggs its mate lays are a brighter shade of blue.
The blue colour in robin eggs is due to biliverdin, a pigment deposited on the eggshell when the female lays the eggs. There is some evidence that higher biliverdin levels indicate a healthier female and brighter blue eggs. Eggs laid by a healthier female seemed to encourage males to take more interest in their young.
Botulism intoxication, which causes the paralysis and death of intoxicated vertebrates, is caused by ingestion of neurotoxins produced by the bacterium Clostridium botulinum. Periodic outbreaks of type E botulism have resulted in die-offs of fish and fish-eating birds in the Great Lakes since at least the 1960s, but outbreaks have become more common and widespread since 1999, particularly in lakes Michigan, Erie and Ontario (Riley et al. 2008). Botulism has been responsible for over 80,000 bird deaths on the Great Lakes since 1999, and extensive bird mortality in northern Lake Michigan near Sleeping Bear Dunes National Lakeshore (SLBE; over 4150 birds in 2007) received widespread press attention and caused great public concern. The actual sites of toxin exposure for birds remain unknown. (via USGS Great Lakes Restoration Initiative - Habitat & Wildlife - Avian botulism in distressed Great Lakes environments)
Type E botulism is not an invasive species and has been present in the Great Lakes system for many years. However, the recent trend of warmer winters has led to more outbreaks. If lake water does not cool enough in the winter, the bacteria are able to start reproducing and this causes problems for birds (especially waterfowl), fish species, and mud puppies. According to an expert who gave a seminar at my college, another outbreak is expected this year.
ScienceDaily (Apr. 23, 2012) — An international team of scientists has uncovered the first evidence of a non-human species cultivating plants for use other than as food. Instead, bowerbirds propagate fruits used as decorations in their sexual displays. The researchers discovered male bowerbirds had unusually high numbers of fruit-bearing plants growing around their bowers, and used these fruits in order to attract females.
Have you ever wondered what (biologically) makes a bird a bird? I thought I would share this list of characteristics that are unique to birds and are not found in any other groups of animals that are alive today:
Feathers — all living birds have feathers.
Horny beak — the jaws of modern birds are covered with a horny sheath, which is much lighter than bone and helps reduce weight to aid flight.
Furcula — commonly called a “wishbone,” the furcula is actually two fused clavicles. Some dinosaurs also had a furcula.
Pneumatic bones — also called “hollow bones,” these special bones have air-filled canals that are strengthened by criss-crossed struts. Some dinosaurs also had pneumatic bones.
Hallux — a special backward-facing toe that helps birds perch or grip prey. The hallux of birds that run along the ground is positioned higher up on the leg, so it doesn’t interfere with movement.
Air sacs — unlike mammals, birds do not have a diaphragm, so air is moved in and out of a bird’s respiratory system through pressure changes in these special sacs. Most birds have nine.
ScienceDaily (Apr. 11, 2012) — Using tiny tags to track a bird’s location, biologists from PRBO Conservation Science (PRBO) have unlocked the mystery of where Golden-crowned Sparrows, which overwinter in California, go to breed in the spring. Published this week in the journal PLoS ONE, the study reveals for the first time the exact migration route of this small songbird to its breeding sites in coastal Alaska.
During a time when birds are experiencing the negative impacts of climate and land-use changes, being able to pinpoint the most important breeding and stopover places is critical to prioritizing conservation investments.
ScienceDaily (Apr. 5, 2012) — Smithsonian scientists and their colleagues have uncovered a new threat posed by invasive Burmese pythons in Florida and the Everglades: The snakes are not only eating the area’s birds, but also the birds’ eggs straight from the nest. The results of this research add a new challenge to the area’s already heavily taxed native wildlife. The team’s findings are published in the online journal Reptiles & Amphibians: Conservation and Natural History.
Burmese pythons, native to southern Asia, have taken up a comfortable residence in the state of Florida, especially in the Everglades. In addition to out-competing native wildlife for resources and habitat, the pythons are eating the native wildlife. Burmese pythons (Python molurus bivittatus) were first recorded in the Everglades in 1979 — thought to be escaped or discarded pets. Their numbers have since grown, with an estimated breeding population in Florida in the tens of thousands.
ScienceDaily (Apr. 2, 2012) — Sparrows in San Francisco’s Presidio district changed their tune to soar above the increasing cacophony of car horns and engine rumbles, details new Mason research in the April edition of Animal Behaviour.
"It shows a strong link between the change in song and the change in noise," says David Luther, term assistant professor in Mason’s undergraduate biology program. "It’s also the first study that I know of to track the songs over time and the responses of birds to historical and current songs."