OVERVIEW
Hello Ploverites! This will be the last breeding snowy plover update for the season. There are no longer any active nests, but two broods of chicks will be fledging by the end of next week! The first of these broods, on Limantour Beach, is projected to fledge this Sunday, September 5, while the second will be fledging Friday, September 10 near Abbotts Lagoon (a total of 2 hatchlings). We have not been able to locate a third recently hatched brood for a couple weeks in the Abbotts Lagoon area, but we are continuing survey efforts to find them south of the lagoon and north going up to Kehoe Beach.
Here are some highlights and summaries from the 2021 breeding season:
- We switched to smaller exclosures (i.e., mini-exclosures or MEs) that measure two feet tall and approximately two to two and a half feet wide, to reduce exclosure visibility to predators and visitors. This has been an effective design for other Recovery Units managing snowy plover productivity.
- Two broods were found in the Abbotts Lagoon area that originated from unknown nests. Both broods fledged three chicks! Unfortunately, we were unable to capture them, as all six were at least a week old when found (i.e., they were too fast for us to capture!).
- We do not yet know the estimated breeding adult population size, but we suspect that it's similar to the 2020 breeding season of around 32 to 36 individuals.
- We confirmed a mother-son plover pair nesting near South Beach, the second case of confirmed inbreeding in the Point Reyes population since the chick banding program began in 2015. The second known case occurred in 2019, which was a brother-sister pair.
- We only observed five confirmed common raven nest depredation events this season, out of 16 failed nests (compared to 12 of 22 failed nests in 2020).
- We observed two nest failures due to unknown predators (possibly common ravens) and nine nest failures due to abandonment and environmental factors (i.e., tides and wind events).
- All three nests on Limantour Beach this season (all from the same female, av:bg!) successfully hatched, and two of these nests successfully fledged one chick! If the current active brood is confirmed fledged this Sunday, September 5, then all three nests will have fledged one chick! Some history about the female associated with these nests: av:bg female actually hatched and fledged from Limantour Beach in 2017 and has bred on this beach every season since (and winters there too!). She was one of three chicks that fledged from her cohort, but we have not observed her siblings in Point Reyes and they haven't been reported elsewhere along the coast.
CURRENT STATS:
- 33 total nests this season
- 0 active nest
- 17 hatched
- 16 failed nests
- 2–5 chicks on the beach
- 22 chicks fledged (the fledge count was initially inaccurately reported as 17)
A newly banded chick, av:yb (aqua violet on left leg, yellow blue on the right leg), sits still as they await for instructions from the dad plover. Abbotts Lagoon, August 20, 2021.
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