Bruce Lyon, a biologist at the University of California at Santa Cruz, always has wonderful bird photos and natural history tidbits based on his work. Today we have A Tale of Coots or Coot Fight Club. We even have one video! Bruce’s words are indented:
I have studied American coots (Fulica americana) on and off over the past three decades in central British Columbia, Canada and thought I would share some photos and biology. Coots look a bit like ducks but they are actually rails. Dirt common (in western North America) and even considered pests (e.g., when hundreds live on a golf course and poop all over the greens), coots are the Rodney Dangerfields of the bird world—like the comedian, they don’t get no respect! Their name is even an insult. Reputation aside, coots are really interesting in terms of their family life and reproductive tactics.
Below: An American coot swimming on its territory. Note the demonic red eye. A couple of other unrelated groups of diving birds have red eyes (loons, many grebes)—I have no idea if this signifies something interesting.
Below: Ideal coot breeding habitat: one of several wetlands where I studied coots near Williams Lake and Riske Creek BC. Coots need bulrushes (reeds) for nesting cover but happily use the dead stems from the previous year, like the ones shown here, so they do not have to delay nesting to wait for new growth. These wetlands have extremely high densities of coots—ten times higher than predicted for a bird of this body size, based on a comparative study of territory size for birds generally.
Below: Coots are fiercely territorial and have ferocious fights with each other. Interestingly, most fights involve immediate neighbors rather than territorial birds trying to keep birds without territories from usurping their territory. Coots apparently forgot to read the textbooks and do not heed the ‘dear enemy effect’, whereby two neighboring territorial animals become less aggressive to each other once territorial borders are well-established. These fights are frequent and occur throughout the breeding season. With all of these fights it’s kind of like watching a hockey game.
Below: The fights are serious and not just ritualized displays—coot talons are large and very sharp and their strong legs result in kicks with a punch. Check out the talons on the birds below. Fights to the death have been reported in the literature. I have never seen a lethal fight but saw a few fights where I thought one bird might drown another. We sometimes find blood on eggs when we check nests and suspect that birds have returned from a fight and bled on the eggs when they incubate. The first time I removed a coot from one of my traps I made the mistake of using my bare hands and paid for this dearly with very badly raked hands.
Below: Both members of the pair fight and it seems that males mostly fight males, and females fight females. Sometimes the whole family gets involved. I recall a memorable scene where the four adults from two adjacent territories were fighting while the kids from the two families sat on the sidelines peeping away (which I anthropomorphically interpreted as cheering their parents on).
Below: When coots are done fighting, they almost always have a little peace ceremony that seems to signal that the fighting is over for the time being. Hockey has its face-offs—coots have their ass-offs™ (not the official name but ‘paired display’ seems boring). [JAC: LOL!] In the display the birds show each other their rear ends, which are adorned with two distinctive white patches (white flags?) and they raise their wings up as well, perhaps to accentuate the white patches. These displays were really helpful for our study because they occur precisely at the territory border—in the photo below the territory border threads the two pairs. The displays allow us to mark the territory borders (with flagging tape on nearest reeds) and later estimate territory size. Most territories hug the shoreline and we measured territory size as the length of shoreline defended. Of all the numerous things we measured about the birds, territory size is the only measure that reliably correlates with reproductive success—the bigger the territory, the more kids produced. This makes sense because the families get all of their food from their territories and bigger territories means more food. This pattern may also explain why coots fight so much—they are fighting to maintain their territory size and ultimately maximize their reproductive success.
Below: A video clip showing the display at the end of a fight (I missed the fight itself). The display often involves a fair amount of pirouetting—repeated spinning around to display the butt and then turning away. The particularly interaction in the video involved two pairs that had their broods close to the territory border. Note the chick begging while its parent interacts with its neighbor.
Below: A coot with a neck collar engraved with a unique number for identifying this individual bird—meet Lucky the coot. I needed to be able to follow known individuals and since coot legs are mostly hidden in the water because they swim so much colored leg bands were not an option so I went with collars. I trapped birds at their nests at night to measure them and attach their collars.
I made the collars myself and I believe I am the only person who ever used them on coots (they are normally used on waterfowl). Therefore, when I walked into the Sacramento Wildlife Refuge in California a few years ago and saw a stuffed coot with a yellow neck collar sitting on the refuge biologist’s desk I instantly recognized one of ‘my’ birds. I had banded the bird in BC and after the breeding season it migrated to the Central Valley of California where it was promptly shot, stuffed and given as a gift to the refuge biologist. Not the happy animal reunion one is used to in the movies. I guess that coot should be named Unlucky.
Below: We use floating blinds resembling muskrat houses to observe coot families. A plywood disk (table) attached to a truck inner tube forms the base, PVC piping makes a dome frame that is covered with a camo fabric cover and then the entire contraption is covered with dried marsh-like vegetation (Cabelas sells panels of dried vegetation for duck hunters to make blinds). We sit on a seat in the blind and sometimes spend 8-10 hours a day sitting in the blinds making observations. The blinds work well and we are sometimes just a few feet from a coot family. In fact, the camouflage is so good that a bald eagle once perched on a blind with a person inside. The blinds are also great for photography and I am often able to get close to various nice marsh birds (a future posting!). The blinds are also great for the occasional practical joke. A cyclist drove by one of wetlands and stopped and stared at the blind I was in. I rocked the blind back and forth and his eyes just about popped out of his head. I repeated the rocking several times and he looked increasingly puzzled and eventually rode off. Perhaps he thought the muskrats were going crazy inside the house.
Below: A typical coot nest hidden in the reeds. Coot nests typically have a ramp down to the water, shown here coming off the front of the nest. The ramps make it easier for the birds to walk up to the nest.
Below: Coot chick are cute and fluffy at hatch. They leave the nest within a day of hatching and follow their parents around the territory while the parents forage. We give each chick a ‘nape tag’ with a unique color combination that allows us to tell the chicks within the brood apart. Nape tags consist of colored beads on a tiny safety pin that is attached to a tiny flap of skin on the back of neck. When we attach the tags the chicks show no signs of distress and there is never any blood so we do not have concerns about the tags harming the chicks.
Below: Coot chicks are fed by their parents: here a parent offers an aquatic insect to its chick. Parental food is essential for the first ten days of life—without it, a chick will perish. The chicks are fed mostly aquatic insect larvae—damselflies, dragonflies and caddisflies, which have to be shaken out of their protective houses before they can be fed to the chick. Note the extraordinary appearance of this newly hatched chick—orange plumes, modified facial plumes that look like beads of wax, blue eyebrows that reflect mostly in the ultraviolet wavelengths, and a bald top of the head (pate) that can change color fairly quickly. Much more to follow on these colors in a later post.
Below: A parent goes below to look for food while its chicks bob on the surface. I suspect that the reason the chicks do not feed themselves is that they are too buoyant to swim under water to search for the food, and they may also lack the experience. When the chicks get a bit older they start to feed themselves by pecking small bits of food off the surface and reeds.
TO BE CONTINUED……
