- Raptor and Closure Updates For May/June
(posted: Jun 07, 2017)
Raptor expert Gavin Emmons shares his raptor activity report for May and into early June as the breeding season progresses.
Raptor and Closure Updates For May/June
posted: June 07, 2017
Prairie falcons (PRFA) and peregrine falcons (PEFA) are actively nesting, with some breeding pairs already producing fledglings (young birds flying for the first time), and others still raising nestlings. A handful of PRFA nests have also failed this season. For the 2017 season, 10 PRFA pairs have been confirmed. Of these, nine breeding pairs nested, and 4 nest efforts failed. Two PEFA pairs are also actively nesting, at Hawkins Peak and General Balconies'''. Both PEFA pairs are a bit further behind in their efforts but are currently feeding and raising nestlings. For information on territory locations and rock formations, refer to Brad Young's climber's guidebook to Pinnacles.
PRFA and PEFA breeding efforts for 2017 are listed below:
- Goat Rock / Resurrection Wall: PRFA pair confirmed, nest successful, fledged 4 young
- Teapot Dome / Tunnel / Egg: PRFA pair confirmed, nest active
- Hawkins Peak: PEFA pair confirmed, nest active
- General Balconies / Machete: PEFA pair confirmed, nest active
- South Balconies: PRFA pair confirmed, nest failed
- Crowley Towers / North Balconies: PRFA pair confirmed, nest successful, fledged 4 young
- Little Pinnacles / Yaks / Yaks Wall: PRFA pair confirmed, nest failed
- Gargoyle / Piedras Bonitas Cliffs: PRFA pair confirmed, nest successful, fledged 4 young
- Willow Spring Slide: PRFA pair confirmed, nest failed
- North Chalone Peak: PRFA pair confirmed, nest active
- South Chalone Peak: PRFA pair confirmed, nest failed
- Drywall Slide: PRFA pair confirmed, non-nesting in 2017
The following territories are currently unoccupied, with no prairie falcons observed within them:
- Pig Canyon
- Scout Peak
- Western Front
- Discovery Wall
- Frog / Hand
- Pipsqueak Pinnacles
- D. Soto Canyon
- Guard Rock
- Rocks West of Chalone Housing
- NE Section 15
- Marion Canyon / Narrows
- North Wilderness Rock
- South Wilderness Rock
- Mating Rocks / Tugboat
The number of nesting PRFA pairs for 2017 is consistent with the 30-year average for the park. However, due to 4 nest failures this season, other measures of nesting productivity - including total successful nests and numbers of fledglings - are below the 30-year averages. Three of the PRFA nests failed while nestlings were fairly well-developed, possibly due to a combination of predation events and disease factors. The fourth nest failure occurred during egg incubation.
Please note that climbing and hiking advisories will remain in effect until the end of June 2017. Posters have been placed on the bulletin board fixtures near the Juniper Canyon trailhead and the Moses Spring trailhead, and advisory signs have been placed near relevant climbing / off-trail hiking areas. Advisory handouts should be available in the Visitor Center and Visitor Contact Station, and are also available on the PINN website.
In addition to PRFA and PEFA, other raptor species have also been quite active at the park. Red-shouldered and red-tailed hawks. American kestrels, and large owl species have been documented actively nesting and producing fledglings. Confirmed nest numbers include 3 red-shouldered hawk nests, 8 red-tailed hawk nests, 3 great horned owl nests, and at least one barn owl nest.
The 2017 breeding season has been particularly productive for long-eared owls - we confirmed 7 nests for the species this year, an annual record for the monitoring program. Long-eared owls are of particular interest as a California species of concern. They tend to reuse stick nests built in previous years by Cooper's or sharp-shinned hawks. See the gallery below for a photo of a long-eared owl fledgling photographed very soon after fledging in May.
Of the 3 great horned owl nests documented this year, 2 failed and 1 successfully produced fledglings. See the gallery below for a photo of nestlings from the site that was successful, a week or two before they young first flew.
Finally, the gallery has a couple of images of prairie falcon nestlings, about a week before they first flew from the nest... Note the remains of a California ground squirrel (the main prey source for prairie falcons) in the lower right corner of the first image.
Here is a "mini-gallery" of sighting pictures from Gavin:
A big thanks to Emma Cox and Megan Gnekow for their ongoing and excellent raptor observations. Emma finished up her second season working with the raptor monitoring team at Pinnacles, and Megan is continuing her multi-year volunteering efforts to assist with raptor monitoring on weekends. Both of them have contributed an enormous amount of information to raptor monitoring and their efforts are much appreciated! If you see us in the office or field, feel free to let me or Megan know if you have any questions or observations to report.
Thank you to all the staff who have continued to provide me with raptor observations; every detail on raptor behavior helps to provide a more complete picture of raptor breeding at the park. If anyone on staff wishes to report raptor observations, I would greatly appreciate it if you please fill out a wildlife observation card, and give it to me or deposit it in my box in the RRM Office.
If you have any observations within the park to report, or any raptor-related questions, please contact me through email or extension 276. Thanks!