*** I am currently in Nome, Alaska working on The Peregrine Fund’s Gyrfalcon Conservation Project with Boise State University graduate student Bryce Robinson. You can read more about this project on previous Wild Lens blog entries ***

Gyrfalcon (Falco rusticolus) nestlings hatch from their eggs after being incubated by their parents for 35-days. 24-48 hours prior to hatching, nestlings will begin ‘pipping’ from inside their eggs. This involves the nestling using a ‘pipping tooth’ located on the top of their upper mandible to poke holes in the egg shell, eventually leading to hatch.

One-day old nestling and pipping eggs.

One-day old nestling and pipping eggs. Note the ‘pipping tooth’ can still be seen on the nestlings upper mandible.

Gyrfalcon nestlings are altricial in nature, meaning they are initially dependent on their parents for nearly everything. Newly hatched birds are often described as altricial or precocial. Precocial nestlings, such as those of shorebirds, can often walk and feed on their own within hours after hatching.

Upon hatching, Gyrfalcon nestlings’ eyes are slightly open and their bodies are completely covered in a layer of downy feathers.

Four-day old Gyrfalcon nestlings.

Four-day old Gyrfalcon nestlings.

After a few days the nestlings eyes become completely open and they begin begging more actively for food. After less than a week the nestlings can move around short distances to reposition themselves for added warmth in the cold subarctic environment.

7-10 day old nestlings.

7-10 day old nestlings.

Early during development nestlings vocalize to their parents, begging for food in a high-pitched voice. After roughly 10-days the nestling vocalizations begin to change to a deeper ‘cack’ more reminiscent of their parents.

At 11-days of age the first flight feathers begin emerging and growing from the birds wings. Wing and tail feathers are the first to emerge and continue to grow throughout the 45-50 day nestling period before the birds fledge.

A roughly 3-week old nestling.

A 3-week old nestling.

We will be entering all the Gyrfalcon nests on the Seward Peninsula for a second time when the nestlings reach approximately 25-days of age. During this visit we will be banding the nestlings with uniquely-numbered U.S. Fish & Wildlife Service aluminum leg bands and recording morphometric information such as nestling weight. Additionally, we will be swapping out memory cards in our nest cameras to examine the composition of Gyrfalcon diet during the early-nestling period.

We should have some very interesting photographs to share from our nest cameras very soon!






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