01 Dec Nature’s Fanny Pack: Fourth of July Monitoring and Fledglings
the birds
Alcatraz is home to many species of birds not just Brandt’s Cormorants and Western Gulls, but also Pigeon Guillemots, Peregrine Falcons (unfortunately not seen this season probable cause bird flu), Black Oyster Catchers, Snowy Egrets, Black-Crown Night Herons, and Great Blue Herons. Through this blog post I have included some of my favorite images I took while on the island showing differences in personalities!
UP, UP, AND AWAY
Nesting season on Alcatraz has slowed down for Western Gulls and flight school has just begun! Chicks are using stretches of pavements as a ramp to learn how to use their wings and catching gusts of wind allowing them to float in the air for seconds before taking a tumble back on land. A lot of our Brandt’s cormorant chicks can now be seen off of the island on its shores in groups which usually they fish by themselves, but them being young prefer each other’s company most likely learning from one another. Gull chicks can be seen floating on the ocean too sometimes with an adult, but they do not dive as deep around 1-2 feet to catch prey as Cormorants do.
Brandt’s Forever Season
A rare phenomenon is brewing on the island…Brandt’s cormorants are double clutching! A rare to never before seen occurrence has been unfolding these past few weeks as some of our pairs who have fledged their chicks are now laying other clutches. We believe that the bay has been doing so well prey-wise with large amounts of anchovies that it’s encouraged double clutching for our older more experienced Brandt’s cormorants! Anchovies during this time can be found all along the California coast from Southern to Northern and with temperatures changing the San Francisco Bay might just be the new center spot for these little fish. This turning into a hotspot for anchovies has attracted Brown Pelicans which are usually in SoCal during this time of year and could also be the result of having lots of whales appear in the bay. Southern California has taken a hit with their grey whales this year as a possibility of malnutrition and low calf counts.
MINE, MINE, MINE, MINE!
The gulls on the island have been a huge bonus to my experience on the island! Some pairs having nested in the same spots for years now are very vocal about it :) I saw a range of personalities from some of these pairs and received head strikes from aggressive parents (rightfully so!). They are the alarm systems of the island with any large bird that appears unordinary, hundreds will flush it and even kill it through exhaustion. This disturbance appears similar to the video below of gulls following a service dog (it’s thought that they confuse dogs with coyotes).
Pigeon guillemot
These guys are hard to miss with their distinct high-pitch screechy calls during fights on the water with each other! They do look similar to our rock pigeons on land, but are much feistier.
Black Oyster Catchers
On the island this season, we had a couple of BLOY pairs, one of which successfully hatched two chicks (later consumed by gulls). They have striking coloration on their beak, eyes, and legs standing out!
Fourth of July monitoring
Every year, monitoring occurs on this holiday to study disturbances with firework shows around San Francisco. Monitoring began at about 8:30pm for the initial big firework commencement and we monitored every 30 minutes until it was too dark to see. Every 30 minutes we were doing counts of the BRAC to note how many flushed. Some of our plots flushed more than others resulting in some adults off of nests as well as some chick mortality. The distress in birds was something I had never seen before and was sad to see as I had become emotionally invested with the plots we have been doing productivity plots for.
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