Blog # 387 One Bird Too Many
Ursula, Orpheus’ new mate, flies off the nest with him looking on, courtesy of Cynthia Sedlacek.
Events are playing out at the Salt Point Osprey nest that are jaw-dropping. Highly territorial around their nests, most female Ospreys have hair triggers for other females that dare come near. For the third year in a row, however, Orpheus has demonstrated his appetite for the ladies, and twice this season Orpheus has flirted with a very rare form of polygamy—two females on one nest. These may not be new behaviors for Ospreys—there are scattered reports of this type of polygamy in the Osprey literature, none of which led to offspring—but they are just beginning to be documented thanks to the advent of nest cams filming every intimate detail of the lives of these birds.
In the last few years, the Salt Point Osprey nest camera has revealed aspects of their breeding behaviors that were not visible to observers on the ground. For instance, Orpheus uses his legs to push the inner nest material into a round egg cup; both birds turn the eggs by gently kicking them with their talons as well as rolling them with their beaks and mouths. The adults flatten the sides of the bowl nest as the nestlings grow and need more room. The parents also soften thin twigs, grass, and leaves with their beaks to make them pliable for nesting. These are noteworthy behaviors, but what has been going on at the Salt Point nest this season is by any metric very odd.
Ospreys are considered monogamous, but proximate nests within eyesight of each other can promote polygamy among these fish-eating raptors. The drama began because the Salmon Creek nest was erected only 150 yards from and in direct sight of the Salt Point nest, which stimulated Orpheus to guard both nests. Orpheus arrived at the Salt Point nest on March 22, 2022, after migrating from South America. His mate Ophelia has joined him a day or two after his arrival for the last nine years. However, this year, Ophelia did not appear. Five days later (March 27, 2022) a new female took her place. With Ophelia nowhere in sight, Orpheus and the new female, Ursula, formed a pair bond. Ophelia finally arrived on March 30, three days after Ursula had commandeered the nest. Normally, Ophelia would have
Ursula with her dark necklace, courtesy of Cynthia Sedlacek.
displaced the usurper, but she did not. For the next three days, Ophelia visited her nest of nine years and sat there with both Orpheus and Ursula in a crowded, uneasy triangle. Orpheus focused his attention on Ursula and no longer fed or copulated with Ophelia. This was perhaps the confidence Ursula needed to maintain control of the Salt Point nest, forcing Ophelia to move to parts unknown. Sadly, Ophelia has not been seen since April 2, 2022.
On April 14, the plot took yet another strange turn when another female—let’s call her Madame X—became interested in the Salt Point nest and dared to land on the nest for the first but not the last time.
Orpheus tries to prevent Madame X from landing on the nest.
Ursula screams in alarm as Madame X flies over the nest.
Each day heavily necklaced Madame X would fly high overhead, slowly approaching while circling. The breeding pair would cry out frantically in alarm and try to chase the interloper away, but that would not deter Madame X from landing on the nest. The resident couple usually took a few seconds to drive
The heavily-necklaced Madame X, courtesy of Karel and Cynthia Sedlack.
her off, but not always. Madame X would assume a head-and-tail-down submissive pose and sit on the outside of the nest unopposed by Ursula for 2-4 minutes before departing.
Ursula flies home to find Madame X and Orpheus in the nest.
Peacefully sitting together, Ursula on her eggs and Orpheus looks at a submissive Madame X.
Orpheus dives at a submissive Madame X (center) while Ursula protects her eggs.
On April 26, Madame X landed on the nest five times, staying there for nearly 5 minutes at a time. The first encounter was particularly odd and had strong sexual overtones. While Orpheus was incubating the eggs he spotted Madame X circling the nest. He cried out in alarm and walked around the nest furiously beating his outstretched wings. Ignoring this clear warning Madame X landed and crouched on the nest edge with her head lowered defensively. Orpheus continued beating his wings, visibly agitated and confused. He made four feeble attempts to mount Madame X before sitting beside her. Ursula returned and stood off to the side before making her way to the uncovered eggs. Orpheus repeatedly tried to push Madame X from the nest, pushing, shoving, and biting her before flying off leaving the two females alone, with Ursula incubating. As soon as Orpheus left the females, who had been posing like statues, they came to life and started looking around the nest and at each other. Orpheus began diving at Madame X repeatedly trying to forcibly drive her away from the nest and hitting her head in the process. When he left, the two females once again sat in the nest casually looking about. Orpheus circled the nest and dove at Madame X again. Just before contact could be made, Madame X took off with Orpheus in pursuit.
A few hours later, Ursula cried out in alarm as Madame X and Orpheus both converged on the nest, Orpheus with a fish. Despite Ursula’s cries and Orpheus vigorously flapping his outstretched wings, Madame X landed on the nest. Orpheus met her outstretched wings, engaging in a pushing match. Ursula stood and began beating her wings aggressively while Madame X crouched submissively with head and tail lowered. The three sat uneasily for a long 10 seconds before Orpheus took flight, circled the nest, and flew over the visitor’s head, smacking her head with the fish. The scare tactic didn’t work. The two females, left alone in the nest, were calm but uneasy as Ursula chirped quietly. Orpheus flew in another circle and dove a second time at Madame X as she lowered her head. Ursula walked about looking at her with interest. Just as Ursula chirped and moved closer to this strange female in her nest, Orpheus flew over and harassed her a third time. The females relaxed their postures and sat quietly with
(L to R) Madame X, Orpheus, and Ursula in a peaceful moment.
an uneasy peace for nearly three minutes. Finally, Ursula had enough. In full alarm mode, with wings spread and beating frantically, Ursula screamed and physically pushed Madame X off the nest. Ursula continued beating her outstretched wings and crying. Ursula continued to chirp as Orpheus chased Madame X away.
Confrontations like this with a nest full of eggs can easily end with broken eggs. Tolerating a second female on the nest a dozen times in as many days is such odd behavior. It is not clear if Orpheus welcomes Madame X's visits or not. He seems conflicted as illustrated by his half-hearted mating attempts. Ursula does not seem overtly threatened when left alone with the intruding female.
Madame X has not been fed at the nest nor has she copulated with Orpheus, at least, not on camera, so these encounters are not fully polygamous, but there is intent. Does Orpheus or Ursula know Madame X—a familiar neighbor or kin? Alan Poole (1989) proposed that when resources are scarce, Ospreys will share their nest with a sister or a daughter. However, resources in the area are plentiful. Perhaps there is a shortage of breeding males in the population, but this seems unlikely. What could Madame X’s motivation be for her unusual behavior? Poole suggests that a secondary female, like Madame X, may stay around betting that eventually the primary female, in this case, Ursula, will fail to breed or dies.
Such polygamous behavior is exceedingly rare—eluding explanation but not the constant eyes of the growing number of nest cams. More such footage can be found on the Salt Point Osprey Nest Cam’s “Polygamous Relations” playlist. A national search of other nest cams revealed two more analogous examples of this atypical behavior. Florida’s Captiva nest cam showed an intruder sitting with a breeding pair for a few moments, and the Savannah nest cam presented an intruder flying in and calmly perching on a branch of a tree next to a male and female in their nest. The round-the-clock eyes of nest cams will help elucidate more aspects of polygamous relations as well as uncover other mysteries of the inner sanctum of the Osprey nest.
Eyes to the sky!
Candace
Candace E. Cornell
Friends of Salt Point, Lansing, NY
Cayuga Lake Osprey Network, Ithaca, NY
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