Murphy the bald eagle waited day after day in his modest, yet carefully built nest for his one egg to hatch, but his keepers did not have the heart to break the news to him: The 31-year-old flightless bachelor was sitting on a rock.
A usually mild-tempered bird, Murphy gently rotated his rock, less shaped like an egg than a small meteorite, as though to incubate it. He lay in the one spot all day, rising to squawk and charge at the other birds that dared to come near his nest at the World Bird Sanctuary in Valley Park, Mo.
A sign on the eagles’ enclosure attempted to abate visitors’ concern, noting that Murphy was “not hurt, sick, or otherwise in distress.” The sanctuary, acknowledging the bird’s behaviors, wished him the best of luck.
Perhaps it was fate, then, when an orphaned eaglet, just a week or two old, was brought into the sanctuary this month, having survived a fall from a tree during a storm in Ste. Genevieve, Mo., about 60 miles southeast. In a way, Murphy was the “obvious choice” for a foster parent, Dawn Griffard, the chief executive of the sanctuary, said in a phone interview.
There was one concern: He had never looked after more than a rock.
Bald eagles share parenting duties, so it is common for males to incubate their young. Sometimes, birds brood upon objects that are not eggs, because of a spring hormonal surge, Ms. Griffard said.
She noted that Murphy’s case, however, was somewhat unusual. He had lived at the sanctuary since the early 1990s and had never fathered an eagle, nor had he chosen to mate with either of the two females in his current enclosure. But her organization consoled a concerned public.
“Murphy is not sad, so you don’t need to be,” the sanctuary wrote in a Facebook post.
Still, Murphy kept sitting on his rock.
In the preceding weeks, Murphy had become increasingly aggressive, leading the sanctuary to move him, and his rock, to a solo enclosure. But the keepers were moved by his tenacity, and fatherly instincts. “It was kind of like, how can we not do this?” Ms. Griffard said. “How can we not give him a chance?”
The keepers moved tentatively, introducing the eaglet to Murphy’s enclosure inside of a small, heated cage that they call a “baby jail.” Through the wire, Murphy and the chick, who is known only as “eaglet 23-126,” cautiously observed each other. (Fans have implored the sanctuary to name the chick “Rocky,” but it is considered bad luck to name a bird that will be released back into the wild.)
A few days later, the bird keepers introduced the eaglet into the shared enclosure.
“We had no idea how Murphy was going to respond,” Ms. Griffard said.
But Murphy, his rock gone by then, took his role as foster parent seriously. He soon began responding to the chick’s peeps, and protecting it. And when, as a test, the keepers placed two plates of food in front of the birds — one containing food cut into pieces that the chick could eat by itself, and another with a whole fish that only Murphy could handle — the older bird tore up the fish and fed it to the eaglet, Ms. Griffard said.
“You can definitely see the imprinting happening, which is exactly what we wanted,” she added.
There are some things, such as flying (Murphy’s wing is permanently damaged) and hunting, that keepers will have to teach the eaglet later. On Saturday night, a storm swept through the area that is home to the bird sanctuary, Ms. Griffard said, and Murphy did not help to keep his charge dry.
“It was kind of scary,” she said. But, she added by email, Murphy was “doing very well learning how to be a first-time dad.”