Big Bear Alpine Eagle Eyrie
Big Bear Valley, San Bernardino Mountains, California, USA · North America · mountain_alpine
About this place
Examine high-altitude Haliaeetus leucocephalus brood-patch thermoregulation and subzero spring incubation.
For kids: Perch high in snowy mountain pine treetops where devoted eagle parents keep eggs toasty under spring blizzards!
Big Bear Alpine Eagle Eyrie · 360° Habitat Camp
What to look for
- Jeffrey pine treetop eyrie — Pinus jeffreyi vascular brood-patch bowl. Centre the emergent Jeffrey pine crown supporting the insulated stick bowl
- Alpine trout & coot lake — Oncorhynchus mykiss & Fulica americana prey. Locate the ice-free open-water patches supplying trout and waterfowl
- San Bernardino snow-storm crest — Orographic Pacific winter storm track. Scan the two-thousand-metre granite ridgeline intercepting Pacific winter lows
Source: Bortolotti & Wiebe (1993), Wilson Bulletin; Webb (1987), Condor — Avian brood-patch vascularity & subzero raptor incubation.
Ask together: Why would fluffy feathers actually get in the way when a bird tries to warm an egg with its tummy—just like wearing mittens to feel a warm mug?
Field quiz
Kids' question: How does an eagle parent pass cozy warmth straight from its body into its eggs during snowstorms?
- A special bare, warm skin spot on its chest called a brood patch
- A tiny electric blanket made of pinecones
- Breathing hot fire like a dragon
Answer
A special bare, warm skin spot on its chest called a brood patch
Adults' question: What physiological change creates a bald eagle's brood patch prior to late-winter egg laying?
- Prolactin-mediated ventral defeathering paired with dermal edema and dense capillary vascularization
- Calcification of breastbone feathers into heat mirrors
- Shivering wingtips dipped into thermal springs
- Fermenting pine resin inside the nest rim
Answer
Prolactin-mediated ventral defeathering paired with dermal edema and dense capillary vascularization
360° photo: Amanda Sweeney, Public domain
See it live: Live check: Jackie & Shadow Big Bear Eagle Cam
- By day
- Bald eagles Jackie & Shadow rearranging sticks, Steller's jays, & ravens Reverse sexual size dimorphism makes female raptors ~25% heavier than males, dividing nest defense and agile prey-delivery roles.
- By night
- Night-vision cam: sleeping eagles & nocturnal northern flying squirrels! Infrared nest audio-video famously revealed nocturnal Glaucomys sabrinus flying squirrels foraging pine cones right beside roosting eagles.
Other language: Русский