Grand Lake osprey eggs featured on webcam fail to hatch
When Kent Roorda, a resident of the Grand Lake area, began filming an osprey nest on his property earlier this year, he had dreams of showing high-definition images of eggs hatching in real time.
Unfortunately, that dream has been turned upside down by the harsh realities of nature. In late June Roorda provided an inauspicious update on the status of the eggs.
“I am very sad to report that none of the three eggs have hatched,” he stated. “The normal and average incubation time is 32 to 40 days. However, it has now been more than 50 days.”
Two more weeks have passed since Roorda’s update, and the eggs continue to languish unhatched, as the expectant mother still sits atop the nest in a futile bid to bring her young into the world. The images from Roorda’s live camera, which is still operating, show the mother still sitting diligently upon her nest.
The exact reason the eggs failed to hatch is impossible to know, though Roorda believes the cold weather Grand County saw in late spring, when the eggs were being incubated by the nesting raptors, was a major contributing factor.
“The most favored reason seems to be that, on a couple of occasions, mom left the eggs a little longer than she should have while it was cold outside and the eggs became too cold,” Roorda said.
Matt Smith, an outreach biologist from Bird Conservancy of the Rockies who specializes in raptor work typically involving bald eagles, concurred with Roorda’s assessment.
“The cold and snowy spring we had would likely contribute to that (hatch failure),” he said. “Leaving the nest for too long at a time is a pretty likely suspect. In warmer weather, this might not be as much of a problem.”
Smith noted that other factors can and do play a part in hatching rates too.
“One thing that can definitely influence a pair’s success is the experience of the parents,” Smith said. “It is not uncommon for younger birds to be less successful at rearing young.”
According to Smith, disturbances at nesting sites can also play a significant part in a successful hatching. He also noted that osprey eggs sometimes fail to hatch because they were not effectively fertilized during the mating process.
Food availability is another major factor. Osprey feed exclusively on fish, and during colder years, when lake ice lingers longer than normal, it can become especially difficult for the birds of prey to obtain enough nutrition.
“The availability of food can limit nest success,” Smith said. “If a bird has to spend more time away from the nest to feed itself, or if the other bird is not bringing enough food, that can lead to more exposure for the eggs. If the lakes don’t get clear of ice, that can seriously affect them.”
The live images of the osprey mother still working to incubate her non-viable eggs might evoke a feeling bordering on tragic, but that sense of tragedy should be tempered by the understanding that hatch failures are not uncommon.
According to Smith, a study conducted in Florida, where warmer temperatures help preclude some of the issues faced by osprey in Grand County, found that osprey success rates vary and in some cases a majority of nests see hatch failures.
“This study in Florida found that success is usually in the ballpark of around 40-60%,” he said.
Now that the eggs have failed to hatch, Smith said, the birds will likely linger for a period before beginning their migration south, most likely earlier than they would if the eggs hatched. When osprey eggs do hatch, the parents will usually spend about three months in the area, as the chicks mature and learn to fly and hunt for fish.
Without any young, the birds should begin their journey south soon. Smith said that raptor researchers still do not know exactly what factors drive ospreys’ decisions to begin their migrations, but he speculated much of it is dictated by the day-night cycle and the ever shorter days marking the transition from summer to fall.
Smith said a recent migration pattern study on an osprey from the Grand Lake area, affectionately named Shadow, revealed where some of Grand County’s birds of prey spend the winter.
“We tracked her migration to Mexico, to a large bay called Laguna Madre just south of Matamoras,” he said.
Smith explained that it is very likely other osprey that summer over in the Three Lakes region would spend their winters along the Mexican coast as well.
For his part, Roorda is looking forward to future summers and more osprey chicks. He has watched several clutches of osprey eggs hatch on his property over the years and noted that 2019 was the first year he has seen the eggs fail to hatch.
“Let’s hope that both mom and dad will have better luck in future years,” Roorda said. “They are such incredible parents, and it is sad when a failure occurs. On a positive note, it appears as though mom and dad are in good health and we wish the best for them in the days, months and even the years to come.”
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