Today we’re once again transitioning north towards Ancud. We will be leaving the world of wifi for about ten days so the blog posts will get uploaded less frequently.
We headed to Aucar, which is roughly half way between Castro and Ancud on the eastern coastline of the island. We found 21 unbanded godwits to survey. There were lots of Black Vultures flying overhead, Chiloé Widgeon teenagers swimming around, and a decent flock of Black Skimmers.
Half of the godwits were foraging right in front of a sand bank where the skimmers were roosting. So, I suppose G could have been looking at the godwits when he noticed a metal band on one of the skimmers (you know working hard 😉).
Black Skimmers are a really, really cool species. Look up a photo! They range along coastlines and lagoons in warm waters on both the Atlantic and Pacific coasts. They’re also fairly common here.
“The remarkable bill of the Black Skimmer sets it apart from all other American birds. The large red-and-black bill has the lower mandible longer than the upper. The bird drags the lower bill through the water as it flies along, hoping to catch small fish. Although the Black Skimmer is active throughout the day, it is also crepuscular (active in the dawn and dusk) and even a nocturnal feeder. The sensitive bill snaps up prey upon contact, allowing hunting in low light or darkness.”
– National Geographic Guide to North American Birds
“Common locally around sheltered bays, inlets, and lagoons. Nests and roosts in large groups on low sandbars. Forages for small fish mainly at night in shallow sheltered water, often flying in small groups. Very long wings, simple black and white plumage pattern, and long red and black bill unmistakable. Flight also distinctive: graceful and buoyant, with slow beats of long broad wings. Wingbeats mainly above the body; head always held lower than tail. Executes hairpin turns and smooth banks while foraging; flock wheels in unison.” – Sibley Guide to Birds
Their bill is truly spectacular. I love watching them fly with their lower mandible in the water truly skimming the surface until it closes down on a fish. You occasionally see individuals with broken or short lower mandibles due to this unique behavior - when they contact something less forgiving than a fish. Interestingly, the Black Skimmer is the only Western Hemisphere representative of the skimmer family. The other two species are the African Skimmer and the Indian Skimmer, and they both have similar mandibles and the same unusual feeding method. Also, at hatching, the two mandibles of a young Black Skimmer are equal in length, but by fledging at four weeks, the lower mandible is already nearly 1 cm longer than the upper. Isn’t that cool?
G saw a paper that was published this month about Black Skimmers that we’ve been talking about. We keep thinking about how cool it would be see a USA banded skimmer or oystercatcher, but the presumption is that neither species migrates this far south and rather that these are resident or austral migrants. There’s been very little work on either species in Chile, but G had seen this cool paper about Peruvian breeding skimmers.
A team of researchers working with them in the Amazon rivers put out a few satellite tags and tracked their breeding individuals onto their nonbreeding grounds. They documented the first trans-Andean migration of an Amazonian breeding species to winter on the Pacific coastline. G and I have been this been wondering where these skimmers go when not on Chiloé.
Today G might have figured that out! He noticed that band and was determined to get the code so we could try to report it - to whomever and wherever it was banded. There were three metal banded birds and one with a type of flag we’ve never seen before in the flock. Two of the metal bands say ‘Brazil’ on them and one said 'Bolivia’! Trans-Andean migration alright! We’re hopeful we read one of the codes in full and can find a way to report it to the Brazilian agency in charge of banding birds! Wish us luck!
Month update: We surveyed 35 unique sites with a total of 60 scans (hitting sites multiple times). We’ve found 24 unique green flags from my breeding population in Alaska at nine different sites. Onto February when we do it all again (hopefully!)!