On June 17-18, I visited Lake John to check the Red-necked Grebes that have set up housekeeping there. The birds are continuing incubation in an area of tall emergent wetland grasses. Both adults appear to be trading off incubation duties. The nest is about 35 meters from the road, and even closer to dry land. This is a more secure spot than the original nest that Paul Slingsby and I found on May 30, but still precariously vulnerable to intrusion by dogs and predators. Here's a rough chronology of what is known so far.
-- May 29 - Judith Wright reports she saw adults with nest material this date.
May 30 - Paul Slingsby and I saw a nest being built very close to the road in smartweed that was just beginning to emerge.
June 2, 3 - I found the original nest abandoned, and two new nests under construction. By June 3, they seemed to have settled on the nest in grass.
June 4 - Dave Rowell photographed the nest with what looks like an egg
June 6-8 - Lee and Linda Farrell observed both birds incubating
June 17-18 incubation continues.
With a minimum clutch size of 1 egg and a minimum incubation period of 22 days, the earliest expected hatch date would be June 26.
With a more typical clutch size of 4-5 eggs, June 29-July 3 would be the earliest expected hatch window.
The water level at the lake is dropping, so the moat around the nest could disappear before the eggs hatch. A dicey situation. Threats in descending order of risk to the nest:
Dropping water level
Predators
Dogs of camping fishermen
Wave/wind damage (the site seems well sheltered from this)
Human disturbance
--
Chuck Hundertmark2546 Lake Meadow Drive
Lafayette, CO 80026
303-604-0531
Cell: 720-771-8659
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