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Courtship is preferred, but optional when it comes to producing mallard chicks.
A courtship display by a pair of common mergansers. Her head flat against the water is signaling her desire to mate. The male’s erect tail indicates his agreement.
It looked like rough sex. It turns out it was just standard procedure for mallards.
We have a pair of mallards nesting in the swamp behind our house. I’ve been reading about mallards because of behavior I’ve watched.
The vigorous mating, for instance.
Our mallards arrived as a pair. They would have bonded last winter, perhaps locally, since so many spend the winter here.
The drake of this pair stays close to his mate. He stands guard, upright and alert, when she feeds on shore. I’ve always thought he was watching for predators. Then I read a research report on mallards. It said, “males guard paternity … ”
He’s ensuring that all the ducklings, if and when they hatch, carry his genes. His hen mating with another drake could compromise that.
An unpaired drake flew in to our pond, eventually grabbing the hen by her neck and subduing her. The culmination of that frantic minute looked like copulation. That male also was acting on behalf of his genes.
The literature describes three types of mallard copulation. Pair copulation is solicited by both birds, the result of their bonding and desire to nest. (Even with willing partners this can look rough.)
Forced extra-pair copulation is what I saw. The male of the mated pair might then also force copulation. He would be trying to cover a rival’s sperm with his own.
Paired males also will seek to forcefully mate with other hens. It is the male’s way of ensuring that he will breed successfully one way or another. Because of this, any drake’s chance of all ducklings being his are about nine in 10.
Female mallards prefer a mate with bright bill color and plumage. Journal articles reported that females laid larger eggs when they mated with their preferred male. Larger eggs produce heavier ducklings with a better chance of survival.
I could find no explanation of the biological function that produces smaller eggs from unwanted sperm.
Females value energetic courtship activity when making their mate choice. Such behavior by the drake probably signals that he is strong and healthy.
Courtship involves a set of signals by both birds. Watch for bills jabbing, heads bobbing, nodding or shaking. Watch for the female swimming with her head low to the water.
As in so many relationships, male courtship skills are important. And they improve with age.
Wood ducks nest on our pond, too. I’ve watched our hen perform that swimming display. Always close to the male, she swam with bill flat on the pond surface. A few moments later, the wood duck drake bobbed his head four or five times, then mounted her.
Sex is strictly utilitarian for birds. The wood duck drake was atop his hen for a second.
Ducks are among the 3 percent of bird species that have a penis. This is a topic for another day. Most birds mate by simply turning tails aside and bringing together their cloaca, the birds’ all-purpose vent (for waste, sperm, egg).
The mallard penis, incidentally, can be inches in length, and has a corkscrew shape. It is an interesting story, but again, for another day.
Injury from chemical weapon agents, known as CWAs, may result from industrial accidents, military stockpiling, war, or a terrorist attack.
Industrial accidents are a significant potential source of exposure to chemical agents. Chemicals such as phosgene, cyanide, anhydrous ammonia, and chlorine are used widely. These chemicals are frequently transported by industry. The accidental release of a methylisocyanate cloud (composed of phosgene and isocyanate) was implicated in the Bhopal, India, disaster in 1984.
Chemical weapons first were used in 1915, when the German military released 168 tons of chlorine gas at Ypres, Belgium, killing an estimated 5,000 Allied troops.
Two years later, the same battlefields saw the first deployment of sulfur mustard. Sulfur mustard was the major cause of chemical casualties in World War I.
CWAs have been used in at least 12 conflicts since, including the first Persian Gulf War (Iraq-Iran War). The Iraqi military also used chemical weapons against the Iraqi Kurds during the second Persian Gulf War.
Civilians also have been exposed inadvertently to chemical weapons many years after weapon deployment during war. Some 50,000 tons of mustard shells were disposed of in the Baltic Sea following World War I. Since then, numerous fishermen have been burned accidentally while hauling leaking shells aboard boats. Leaking mustard shells also have injured collectors of military memorabilia and children playing on old battlefields.
Although a number of international treaties have banned the development, production, and stockpiling of chemical weapons, these agents reportedly are stillbeing produced or stockpiled in several countries.
Within the last decade, terrorists deployed chemical weapons against civilian populations for the first time in history. The release of sarin in Matsumoto, Japan, in June 1994 by the extremist Aum Shinrikyo cult left 7 dead and 280 injured. The following year, the Aum Shinrikyo cult released sarin vapor in the Tokyo subway system during morning rush hour, leaving 12 dead and sending more than 5,000 casualties to local hospitals.
Several characteristics of chemical weapon agents lend themselves to terrorist use.
Chemicals used in CWAs are widely available, and recipes for CWA production may be found on the Internet.
CWAs are transported easily and may be delivered by a variety of routes.
Chemical agents often are difficult to protect against and quickly incapacitate the intended targets.
Most civilian medical communities are inadequately prepared to deal with a chemical terrorist attack.
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