Roosters Crow in Pecking Order by Seniority
Roosters crow in order of seniority, the top cock announcing daybreak while juniors patiently wait their turn.
Roosters crow in order of seniority, the top cock announcing daybreak while juniors patiently wait their turn, said a study Thursday which revealed a long-guarded secret of chickendom.
We are all familiar with that first pre-dawn "cock-a-doodle-doo", quickly followed by others within hearing distance.
But how do cockerels decide who goes first?
They pull rank, according to a set of experiments with captive birds reported in the journal Scientific Reports.
"The top-ranking rooster always started to crow first, followed by its subordinates, in descending order of social rank," wrote the Japanese authors of the study.
"When the top-ranking rooster was physically removed from a group, the second-ranking rooster initiated crowing."
Crowing is thought to be a means for cockerels to advertise their territory -- limiting the risk of surprise, potentially aggressive encounters.
Chickens are very social and hierarchical animals, and cockerels, when meeting each other for the first time, quickly settle their pecking order the old-fashioned way -- with a fight.
The strongest, dominant birds subsequently enjoy priority access to food, hens and roosting places.
"Here, we show that the top-ranking rooster also has priority to determine the timing of predawn crowing, and that subordinates are obedient to the top-ranking rooster in a group situation," said the study paper.
The research team placed roosters in groups to establish their hierarchy from the number of sparring victories and losses, then separated them into individual cages to observe crowing behaviour.
Crowing order, they found, was strictly conserved even when the timing of the dominant rooster was earlier or later than the previous day.
Previous research had shown that the timing of crowing is controlled by an internal biological or "circadian" clock, which lower-ranking chickens also have.
The data suggests that subordinate roosters suppress their own natural rhythm, and "are patient enough to wait for the highest-ranking rooster's first crowing every morning," study co-author Tsuyoshi Shimmura told AFP by email.
"The subordinate roosters compromise their circadian clock for social reasons."
Some birds have a flair for the funky when it comes to selecting where to build their nests, finds the
at the Cornell Lab of Ornithology. Now that spring nesting season is underway, don't be surprised if you find a nest in old boots left outside, on top of traffic signals, in gutters and downspouts and at many other surprising locations. This osprey, for example, unintentionally gave the female figure depicted by the statue a "hat." Underway right now is Cornell's "Funky Nests in Funky Places" contest, where entrants can submit photos, videos and more documenting oddly placed nests. "Many people, particularly those living in cities, are not aware of all the wild birds living in in their neighborhoods, believing they would only be found in faraway places," Cornell's Marta del Campo told Discovery News. The challenge, held every spring since 2009, was created to encourage people to discover the kinds of birds living and nesting in their neighborhoods, del Campo explained.
A ladder serves as an avian "condo," since multiple American robins decided to build their nest on it. Del Campo said that American robins, along with mourning doves, house sparrows and certain hummingbird species, commonly build their nests in unexpected urban locations.
Hopefully the owner of this truck in Pennsylvania did not go for a drive for a while! Presumably, the truck had been stationary for quite some time, catching the eye of an industrious American robin seeking a sheltered space. If you find a nest, del Campo and her team urge that you leave it undisturbed. "Even if a nest has been built in a somewhat inconvenient place (for you), be patient," she said. "In a few weeks the birds will be gone. Meanwhile, you get a front-row seat to a wonder of nature. Do not provide food or get too close to the nest because this can attract predators and stress the bird, which might then abandon the nest."
Using spider web to affix its nest to a single bulb in a strand of holiday lights, this tiny Anna's hummingbird successfully hatched two chicks last year.
A goose figurine became home sweet home to a real live bird, a common moorhen. "When birds are looking for a place to nest, they seek specific qualities, depending on the species," del Campo said. "For example, some bird species, such as woodpeckers and chickadees, look for cavities, while hawks like to build on flat surfaces in high places, such as window ledges on tall buildings that must seem like natural cliffs to them." As for the common moorhen, it must have liked its "room" with a view, not to mention the protection provided by the island-like figurine.
The owner of these motorcycle helmets must have been surprised when he found birds nesting in them. "Even in urban areas, we're a lot closer to birds than you might think," Celebrate Urban Birds project leader Karen Purcell said. "This contest is a lot of fun, but it's also about really being aware of what's around you and taking the time to appreciate birds and all of nature."
Neighbors passing by must have given this wreath with an apparent mourning dove "decoration" a second look when the bird actually moved. The dove may have been attracted by the natural materials of the wreath and decided to move in.
Perhaps the nursery rhyme about Old Mother Hubbard was inspired by a sight like this: a Carolina wren's nest in a golf shoe. "All birds are looking for a place where they can be safe from predators and where food and water are handy," del Campo said. "When you look at it that way, some of the 'weird' locations actually make some sense. A bird nesting in an old shoe in your garage will be protected from bad weather and out of view of predators."
By the size of this nest, Big Bird himself could have moved in. Del Campo and Purcell said that BBQ grills actually are fairly common as bird nesting spots. Around houses, birds might also construct their nests in potted plants, on and in light fixtures, on shrubs, atop balconies, under eaves, on doorsills and windowsills.
An American robin selected this urinal in Texas for its nest site. It appears to have been a good decision, based on the many healthy-looking chicks seen in this photo. This location might make Cornell's evolving "funkiest of the funky" list. As of now, the list also includes a great horned owl nest found in a laundry basket on a tree in Toronto, a mourning dove nest on a tombstone in New Orleans, and a European starling nest on retired V1 rockets at the Marshall Space Flight Center in Huntsville, Alabama.
This house sparrow nesting in a dinosaur's mouth seemingly has come full circle, since birds themselves are dinosaurs. (Scientists sometimes refer to dinos as "non-avian dinosaurs" to keep the two groups distinct.) Entries to the Funky Nests in Funky Places challenge are due by June 15, so there is plenty of time to seek out likely subjects. "We are looking for fun and interesting stories about the surprising nests people find in their neighborhoods," del Campo said, "but we do caution people, again, not to get too close to nests. We don't want any harm to come to the birds." Guidelines are at the