Farallon Islands

Cassin's Known-age /  by Michael Johns

One of the more exciting projects we conduct on the Farallones is the Cassin's auklet known-age study, which was first initiated in 1983. The birds are known-age because they are banded as checks, and once those chicks recruit into an unoccupied nest box we can gather valuable information on mate selection and retention, changes in breeding performance with experience and age, and signals of individual quality; all of which help managers better understand how individual contributions lead to population level changes. The work involves checking the contents of over 400 nest boxes distributed across the island, and taking various measurements of adult birds like bill depth, wing chord, and weight, which are used to determine body condition and sex. 

Photo taken through Point Blue Conservation Science | USFWS

April Showers /  by Michael Johns

This spring has been dominated by unsettled weather. We've been receiving a steady stream of moisture from the south, with descent downpours occurring every week. The weather makes for some dramatic early morning scenes, and has also been keeping the yellow flowers of the Farallon weed around for a little bit longer. 

Photo: Point Blue Conservation Science and USFWS

50 Years of Bands /  by Michael Johns

It's been 50 years since scientists from Point Blue Conservation Science (then Point Reyes Birds Observatory) began a continuous monitoring effort on SE Farallon Island. Some of this work includes banding certain species of seabirds to learn more about their movement patterns, survival and mortality rates, population status, and individual breeding behavior and success; all important information guiding management decisions and tracking the potential effects of climate change. Point Blue has amassed an impressive sample of banded birds since work first started in 1967, totaling nearly 125,000 individuals as of 2016. The graphic below illustrates the total bands put out by year and cumulatively since 1967 for 8 target species. 

Navigating With The Sun /  by Michael Johns

One of the easiest ways to study basic life-history and behavior of seabirds is to outfit them with devices the passively record data for you. The tricky part is getting those devices back in order to download and analyze those data. So far this season, we have recovered 19 geolocator tags that were secured to the legs of Cassin's auklets breeding in artificial nest boxes last year. These tags are designed to be very small and light, and have zero affect on the breeding performance and survival of birds that carry them. Geolocators record ambient light levels experienced by the bird as it flies around it's environment. These light level recordings are later used to estimate roughly where the bird was twice a day throughout the deployment period, using the timing of sunrise and sunset (which varies depending on longitude) and the duration of day-length (which varies by latitude). The photo above shows a row of tags calibrating in the sun on SE Farallon Island. 

Noting The Weather /  by Michael Johns

For roughly 50 years now, researchers on the Farallones have recorded daily island weather observations that include the wind intensity and direction, air temperature, and sea conditions. And for roughly 50 years the instruments used to collect these data haven't changed much. This long time series of direct weather observations provides information on meteorological and oceanographic patterns that impact the productivity and success of species that breed on the island, from short-term phenomena such as El Nino, to long-term trends associated with climate change. Recently, strong gusts from the Northwest have been tipping the anemometer needle beyond the 30 knot mark, a good spring wind to drive the upwelling.