data viz

Auklet Family Tree /  by Michael Johns

Part of the basic seabird monitoring work we do on the Farallones involves tracking the reproductive history and lifespan of Cassin’s auklets that were given uniquely marked metal leg bands as chicks. Just over 400 wooden nest boxes were installed across the island in 1983, which mimic the natural burrows used by the auklets, and birds quickly started breeding in them. Over the past 35 years, each box that contained a known-age pair was checked every 5 days to note when an egg was laid, whether or not that egg hatched, and whether or not the chick reached fledgling age. Some of these chicks from known parents recruited into their own nest boxes and started breeding, resulting in multiple generations of birds all within close proximately to each other. Above is a family tree created with the kinship2 package in R, showing the largest pedigree in the known-age dataset that spans 6 generations from 1987 up until 2018. Click HERE for a higher resolution version.

Bill Load of Fish /  by Michael Johns

This animation represents the total number of prey delivered by common murre parents to awaiting chicks during a 14-hour diet watch. Each red dot depicts a single breeding site in one of our followed study plots on Southeast Farallon Island. Circles appear when a fish is delivered, and intensify in color as more fish are brought in throughout the day. Common murres deliver a single item after each foraging trip, the size and species of which are identified by Point Blue field scientists as birds fly into their respective sites. On this particular day in 2016, foraging parents were bringing in predominately anchovy, followed by juvenile rockfish and a mix of less common items such as squid, smelt, flatfish, and juvenile salmon.

Kilowatt Plot /  by Michael Johns

Kilowatt hour (kWh) is the standard unit of energy consumption, equivalent to 1000 watts per hour. For example an electric oven that consumed 1000 watts in an hour, or 100 watt heater that ran for 10 hours, both used 1 kWh of energy. On average, according to the US Energy Information Administration, an American household consumes just over 850 kWh per month. Looking at this plot, where each blue dot represents total kWh used each month, even in the dead of winter here in Alaska Casey and I stay well under the national average. Of course we don’t have an kids, don’t have air conditioning, and live in a small 800 square foot cabin heated by burning oil. Still, temperatures regularly dip below -10F in the winter, and we have to do things like plug in our cars to keep the engine oil warm, so I think we’re doing alright. Just for fun, I fit a simple linear model to our monthly energy consumption, which takes into account average monthly low temperature, day length on the 15th of each month, and number of days per billing cycle. The model (yellow line with shaded confidence region) predicts our monthly usage pretty well, tracking lower consumption during the longer warmer days of summer, and higher consumption during longer colder nights of winter. Of course the model isn’t perfect, but something odd did happen during the months leading up to 2017. A mystery that has yet to be solved.

South of a Sunburnt Country /  by Michael Johns

Using a gridded sea surface temperature dataset from NOAA, and a handy orthographic projection of Earth centered on the South Pole, you can see Tasmania hovering just above a cold ring of water wrapping around the frozen continent of Antarctica. Although a part of the sunburnt country of Australia, Tasmania’s southern position and proximity to this cooler band of ocean temperatures gives the island a more temperate climate. February in the Southern Hemisphere means shorter days and cooler nights, marking the beginning of a transition to fall. Cooler temps and rain couldn’t come soon enough, as the whole of Australia has been hit with the one of the most extreme heat waves on record, with bush fires sparked by lightning strikes raging across much of Tasmania. These heat waves may become the new norm for this and many other parts of the world, as global average temperatures begin to creep up from a long-term baseline. While not as pronounced as places like the Arctic, records indicate sea and air temperatures are slowly on the rise for this unique southern island of Australia.

Graphics created in R with packages ggplot2 and touched up in Photoshop. SST data are interpolated high resolution average daily values for January 30th, 2019. I tested out a cool new package put out by the BBC graphics team on the temperature anomaly plot, which allows you to apply the graphing styles they use for publications. Check out the link HERE.

Where Are the People? /  by Michael Johns

Aside from a major city and a handful of townships, Tasmania is mostly an island of rugged landscapes and remote wilderness. There are roughly 522,000 people currently living on this island state of Australia, nearly half of whom reside in the greater Hobart region; Tasmania’s only city center. The heat maps above depict the spatial distribution and densities of people across the island. Each circle represents a 0.05 x 0.05 degree pixel within a larger spatial grid, colored by the total number and density of people within each pixel. Rather than using a raster or contours to display the population data, I went with a simple grid of points using the package ggplot2 in R, which I think gives it a retro “Lite-brite” look. If you never had one as a kid then you missed out. Hobart glows red hot, followed by the town Launceston (called “Launy” by the Aussies) and the northern coastline. We will be flying into Hobart and exploring the city for a few days, before heading out in a camper van rental to check out some of the darker corners of these maps.

Population data used to create the maps above can be found at the following link: http://sedac.ciesin.columbia.edu/data/set/gpw-v4-admin-unit-center-points-population-estimates-rev10/data-download

Rather messy but mostly functional R code used to make maps can be downloaded HERE.