Planet Earth II, the new BBC documentary narrated by Supreme Voice of Nature Sir David Attenborough, devotes one of its six episodes to animals living in cities. It’s unsurprisingly great. (Even if the ultimate masters of urban living, pigeons, who you might expect to be celebrated in this context, instead spend the episode getting unceremoniously eaten.) The “Cities” episode has to walk a delicate line, heralding animals’ ability to adapt to human landscapes without failing to acknowledge that humans overwhelmingly destroy habitat rather than creating it. It mostly leans to the optimistic side of the line; one segment makes New York City seem like a wildlife paradise.
The darker side of cities is represented by a segment on hatchling sea turtles. The turtles use the shine of moonlight on water to guide them from their nest in the sand into the ocean. Unfortunately, we humans love to shine lights even brighter than the moon, and more than half of the tiny turtles are drawn away from the ocean by the city’s lights.
A hatchling Hawksbill sea turtle in Planet Earth II.
As Attenborough narrates, footage rolls of the baby sea turtles gamely clambering across sidewalks and onto busy streets, heading for the ocean that isn’t there. The bodies of roadkilled turtles are visible in the background. One turtle makes it across the street, then tumbles halfway into a storm grate and gets stuck, lost to view save for one forlornly-waving flipper.
As soon as the episode ended, I began typing into Google: “planet earth 2 did”—at which point Google helpfully autocompleted the rest of the sentence: “planet earth 2 did they help the turtles“. Everyone else who had seen the episode wanted to know, too.
Like elephants or dinosaurs, male Northern elephant seals on land are massive past the point of useful reference. A 5000-lb animal falls off our everyday mental scale; it’s just enormous.
Yet, lounging around on the sand at this time of year—their mating season—these beasts look like they need some band-aids and Neosporin. Their thick, strong hide is marred with new gashes laid over old scars. Titans they may be, but even titans can fall when they square off against other titans.
Two males facing off. The male on the left has blood on his nose.
I’m teaching an Animal Behavior course this semester. The lectures are 80 minutes long and exactly during the sleepiest time of the afternoon; I enjoy the challenge of getting a reaction from the students under these circumstances. Videos of baby animals in peril always get attention (some good ones: marine iguana, barnacle goose, water buffalo), but they’re so reliable it almost feels like cheating.
My students have actually broken into applause during lecture three times so far. One of these will not be discussed in detail (it involved the recitation of poetry), but the other two were in response to two quite different animal accomplishments, which I thought I would share.
This Chestnut-backed Chickadee is molting his head feathers, hence the odd colors.
After breeding, if you’re a bird, comes molting. Time to discard those old, worn, raggedy flight feathers and start with some fresh ones for the long haul of the fall molt, or replace sparse downy feathers with good warm ones for the cold of winter. This means that around now—from mid-July to September—you may see a lot of birds who aren’t looking their best.
The egret chicks at the nesting colony are growing. They’re doing some neat stuff as they grow, like practicing walking very carefully along branches.
But they are also getting up to a lot of nonsense.
Siblings! No fighting, no biting!
The birds are having babies, those babies are learning to fly, and they are flying into our nets at the banding station. They’re not really babies by this point: most of them are independent of their parents. They may have been out of the nest for a month or more, and are technically “juveniles” or “immatures.”
At the banding station we collect data on each bird we catch, including that bird’s age. It’s important to record the age if we can, because the more accurate we are with the age the first time we catch a bird, the more accurate we can be later. If we caught a bird in 2014 and recorded that it was a juvenile, then when we catch it in 2016, we’ll know it’s exactly 2 years old. If we didn’t bother to age it back in 2014, then in 2016 we would only know that it was at least 2. That maybe seems like a small distinction, but the lifespans of wild birds are still an area in which we lack a lot of information, so knowing exact ages is valuable.
How do you tell if a bird is a juvenile or an adult? In some species, the juveniles are dramatically different colors than the adults. Juvenile juncos, brown and streaky, look distinct from adults even from a distance—until they molt, at least. But the differences can be a lot more subtle.
Here is a Common Yellowthroat from the banding station:
How old is it?
Ranitomeya imitator giving his tadpole a piggy-back ride. Photo by John Clare*
You can find poison frogs at zoos, aquaria, and some museums now: tiny and colorful, often hard to see in the vegetation-rich tank until— oh! all those little blue things, that’s them! They’re so pretty! You watch for a while, and they sit on their leaves unmoving, doing accurate impressions of the plastic toy frogs being sold in the gift shop, until you get bored and move on to the next exhibit.
They have a secret: they have rich lives full of interesting behaviors. They just aren’t interested in doing those behaviors in front of you.