(First appeared in Orlando Sentinel March 23, 2009)
The sandhill-crane eggs are gone. I don't know how it happened or exactly when, but the day after I watched the nesting pair scare away two other sandhill cranes, a misguided turtle and a murder of crows, I realized their eggs were missing.
What I actually noticed was an unattended nest. Until then, one or another of the cranes dutifully sat on the eggs day and night. Male and female cranes share incubation responsibilities, so I could never be sure which bird was keeping the two eggs warm. Except when they flew off in tandem to chase away other birds, one crane was always there.
The morning I realized the eggs were missing I also saw the season's first alligator glide through the shallow water. Our family regularly uses the lake for swimming. Monitoring the alligator population is an activity I take seriously.
Every year about this time, one or two of the toothy reptiles discovers our 12-acre watering hole. This year's visitor was relatively small — maybe 4 feet long — and too little to pose a serious human threat but large enough to devour sandhill-crane eggs.
Then again, the egg robber just as easily could have been a fox, raccoon, crow, owl, bobcat, coyote or even the osprey that regularly roosts on the lake-top platform my husband built. We have no shortage of predators willing to fight for a mouthful of crane eggs or hatchlings.
If that's what happened, it must have been quite a battle. When under attack, sandhill cranes command an arsenal of weapons. Their large stature and 6-foot-wide wingspan can be imposing. Add to that a pointed beak for poking, strong legs for kicking and a bellowing voice that doesn't let up, and you have the means to stop most enemies in their tracks. Unfortunately, even the best weapons don't always work.
A study of 1,096 sandhill-crane clutches at the Malheur National Wildlife Refuge in Oregon from 1966 to 1989 showed coyotes destroyed 20percent of the eggs, ravens killed 15percent and raccoons destroyed 9percent. I know all three predators frequent our property, but ravens or perhaps crows have been most visible. The Oregon study noted the obvious: Well-concealed nests resisted the most predation.
The cranes in my lake must not have read that report, because their nest was as exposed as could be. Stuck on the end of a barren sand spit in the shallow water a mere 20feet from shore, the roughly composed structure was visible to any potential egg-eaters and easily accessible.
I'm not surprised the two eggs vanished, but I am sad. Unlike birds that may lay multiple clutches yearly, sandhill cranes nest only once. When eggs disappear, chances of another clutch by the same birds in the same year are nil.
Meanwhile, the male and female cranes continue to roost on the same sandbar by their empty nest. During the days, they wander about together, foraging for food, preening their feathers and raising their voices to bellow to any other sandhills that chance to fly overhead.
Is their vocalization a warning to others to stay away, or a message of mourning to announce their loss?
It is anthropomorphic to attribute human feelings to animal behavior, but when something like this happens, it's hard to avoid such speculation. That's especially true with animals such as sandhill cranes that forge strong parent-child bonds. Although immature cranes can fly only 10weeks after hatching, they usually remain with the parents for a full year, staying together until the elders are ready to lay another clutch of eggs. Only then will the young colts — immature cranes — venture off on their own.
My nesting couple won't raise babies this year, but that doesn't mean their child-rearing days are over. Sandhill cranes can live in the wild for more than 20years. They tend to return to previous nesting sites year after year, so it's likely we'll have several more chances to observe the life cycle of these fascinating birds.
With so many future chances, it's quite likely their next egg-laying experience will be a success. I certainly hope so. A pair of Carolina wrens is building a nest under the eaves of our house. Watching them scurry back and forth with building materials has helped ease my feelings of loss.
It's hard to keep things in perspective when emotions get in the way. Losing the eggs is a disappointment, but it's not without an upside. Those eggs nourished some animal that also may be raising young. Life is full of ups and downs. One critter's loss is another animal's gain.
As for me, I'm in awe of the cycle. Life goes on no matter what, for birds as well as people.
It is sad about the loss of the eggs. And I never thought about the aspect of them feeding some other critter. This was an interesting post. Sounds like you have a wonderful view of nature where you are.ReplyDelete
Hi Sue - the wildlife has expanded greatly over the years as we've done more and more planting. It really is a joy watching it allReplyDelete