Who doesn’t need a shot of color during the mid-winter blah outdoor landscape of white, brown, and gray? After a monotonous week of fog and gray weather, it was time for a visit to the indoor tropical room of Como Conservatory in St. Paul, MN. Each time I go I find a few new species that have taken up residence there.
Of course I love watching birds in the backyard, but I don’t especially love what some of them do to my house. The woodpeckers are at it again, drilling holes into the redwood siding of the house and the garage. The little Downys do a lot of damage by themselves, but this morning the local Pileated Woodpecker got into the action, and started hammering on the garage with some serious blows.
Looking back over this year’s photos, I found some gems I had overlooked at the time they were taken. During our birding explorations of southern Spain in April-May of 2022, we visited La Dehesa de Abajo (literally, the meadow down below).
The Dehesa is a nature reserve just 15 miles southwest of Seville located within the greater 52 square miles of the Donana national park and nature park system.
Among the many wonderfully different birds we saw at the Dehesa, the European Bee-eaters were the most colorful and interesting (to me) to watch. These vibrantly colored, slender birds are distant relatives of Kingfishers, but are only found in southern and central Europe, parts of northern Africa and western Asia during the spring and summer. After breeding there, they migrate to tropical Africa for the winter.
Pairs were actively foraging for insects among the flush of wildflowers in the meadow, with males often bringing food to females, and perching near them. In fact, couples were perched everywhere — often next to each other in small groups.
European Bee-eaters are highly gregarious and nest colonially in sandy banks, into which they excavate 5-foot long tunnels for their nest. Both parents incubate the eggs and feed the 5-8 offspring to fledgling. Once out of the nest, adult and juvenile Bee-eaters roost communally in long lines of birds huddled closely together.
Despite their name (and they do eat a lot of bees, wasps and hornets), male Bee-eaters catch larger items like dragonflies and butterflies to feed to their mates during courtship. We watched a pair of Bee-eaters in this ritual for a few minutes as the male made several trips to feed his mate. The first image is a composite of his flight in. The second image shows him bringing a dragonfly to her (barely visible in his beak), and the third composite image shows his departure on another foraging trip.
Although Honeybees do make up 60-80% of their diet, their collective impact on the bees in an area is minimal; studies found that they ate less than1% of the worker bees from a particular hive. Bee-eaters do remove the sting from the bee before swallowing by bashing it against a tree limb or fence post.
Such gorgeous little birds, and such fun to watch. But there is much more to see in this richly diverse area of Donana, Europe’s largest national park. More on this topic later.
What do these animals have in common during the fall months?
The answer to the question above is that all of these (and many more bird and mammal species) exhibit excessive consumption of food in the fall, technically becoming hyperphagic.
There really are only a few viable solutions to surviving the long, cold winters of the far north: 1) get out of town — migrate! 2) build fat stores to last you several months and sleep as much as possible, and 3) stay active to search for what little food remains, tolerate the cold, but enter a starvation state by metabolizing a lot of of your muscle (when you run out of fat).
The temporary condition of hyperphagia is brought on by decreasing photoperiod — i.e., the continually declining number of daylight hours in the transition from late summer to fall — that triggers the change in an animal’s eating habits. Fortunately, this also happens to be when food is most abundant with the ripening of seeds, fruits, excess numbers of young, naive juvenile animals roaming the countryside, etc. So food is easy to come by and fattening is easily accomplished by overeating.
To take Black bears as a good example of this strategy, consider the following comparisons of its diet and caloric consumption from summer to fall.
In the summer Black bears consume about 5,000-8,000 kilocalories per day. If food and water are restricted at this time, they break down their muscles for energy, may accumulate too much nitrogenous waste in their blood, and may die. They cannot “hibernate” at this time.
In the fall, Black bears become voracious, begin consuming 15,000-20,000 kilocalories and drink gallons of water per day, excreting 1-2 gallons of urine as they metabolize all those calories into fat stores. Then, they stop eating and enter a lethargic, hypo-metabolic state of winter sleep, in which their resting heart rate of 80-100 beats per minute falls to less than 22 per minute and their breathing slows down to 2 or 3 times per minute. For the duration of their winter “sleep” they don’t eat, don’t drink, don’t break down any muscle, and females give birth to their cubs. It’s an amazing physiological transformation.
But have you ever wondered if we humans exhibit a similar response to the waning photoperiod and colder days of fall weather? It’s true that humans cannot hibernate the way small rodents do, but could they increase their consumption of carbohydrates and fatten up in the fall and then decrease their daily activity and sleep more in the winter to conserve energy — like bears do? [Side note: carb craving in the fall is a real thing for me — how about you?]
Well, here is the answer, in an article from the New York Times written more than a hundred years ago, back in November 1906. (Click on the image to enlarge it to be readable.)
Apparently, it has been common practice in some cultures (in the past?) that face temporary periods of starvation in winter to prepare multiple loaves of substantially nutritious bread in the fall, prior to beginning a routine of reduced activity and increased bouts of sleeping during long winters. Sleeping with farm animals for warmth was encouraged, I guess.
I’ve visited quite a few famous caves in the U.S., but the amazing caverns carved from karst limestone near Postojna in southwestern Slovenia are the most spectacular I’ve ever seen. They are definitely one of the Wonders of the Natural World.
The Postojna cave system is notable because of all the animal life found there. Over 100 species have managed to survive in the dark, cold (45-50 F), mineral-rich water, including a cave beetle species, a jelly fish relative, crustaceans, pseudo scorpions, and a cave spider species. But the largest and most remarkable cave dweller in Postojna cave is the “baby dragon” or cave salamander or Olm (Proteus anguinus).
There was some excitement among the cave biologists several years ago when one of the large Olms began to lay eggs. It took quite a while but she eventually laid more than 50 eggs, about 20 of which hatched in about 5 months. The youngsters had normal eyes, but they regressed in size and skin eventually grew over them. When presented with small worms, Olms immediately go on the attack, hoovering them up (like a vacuum cleaner) with their elongate snout.
There were a few European or Eurasian representatives of the mammal fauna in the Zagreb zoo, but most of their mammals were native to Africa and Southern Asia. The zoo here has done an excellent job of providing as much natural habitat for the animals as possible, while still allowing them to be easily observed by zoo visitors. Enclosures with clean, clear glass facing zoo visitors allowed photographers up-close looks at the animals, and occasionally direct contact with them looking back at us. What a treat!
While we walked around the zoo, we could hear a male lion roaring intermittently. When we finally found the lion enclosure, the male was sleeping next to an old rubber tire — not exactly the perfect pose for the king of the jungle.
Zagreb, capital of Croatia, is a bustling city of old and new — ornate buildings dating to its boom period as part of the Austria-Hungary empire and sleek high-rise skyscrapers built after the Balkan War. There is a lot to explore in Zagreb, and many unique dishes to try, but yesterday afternoon was the time to explore the Maksimir Park Zoo. The zoo exhibits were spacious, nicely landscaped areas with glass separating animals from humans, which allowed me to get some good close-ups. Birds from Europe and Africa were pretty well represented.
Sometimes you’re the predator, sometimes you’re the prey…
I walked around a small reconstructed cabin at Fort Ridgley state park wanting to peer in the windows at the back and see what the interior looked like.
In the process I almost stepped on a leopard frog sitting in the grass near the sidewalk. The frog jumped to the base of the cabin, scaring a grasshopper (that I presume had been sitting on the sidewalk) to jump higher on the wall to avoid the frog.
But then I noticed a “pack” of garter snakes creeping toward the corner of the cabin near the frog.
Local Minnesota photographer Paul Sundberg captured just such an event on a recent canoe trip in the Boundary Waters when he spied a garter snake engulfing an American Toad. Once consumed, the toad made quite a large bulge in the snake’s body.
Sometimes you’re the predator — sometimes you’re the meal! And so on up the food chain.
It’s too early for us (humans) to start thinking about winter with its short days, cold temperatures, and blah landscapes. But not too early for the 13-lined ground squirrels that live out on the short grass meadows and prairies near Fort Ridgley state park. For them, it’s a race to eat enough to fatten up so they can hibernate in their deep burrows before cold weather arrives and the grasses dry up and their seeds disperse.
These ground squirrels are aptly named for the 13 dark brown and white stripes that line their backs. They can be found anywhere there are grassy meadows in the central part of the North America from Texas to southern Canada. But you’ll only find them above ground for about six months of the year. The rest of the time they are hibernating (deep sleep) in a deep burrow beneath the prairie plants.
The coloration is apparently good camouflage for them as they run through blotchy patterns of grasses heavy with dark stripes of seed heads, and the striped pattern may help reduce their visibility to their number one predator – the Northern Harrier.
Sometime in October all the ground squirrels will disappear underground to sleep away the winter cold in a state of torpor in which respiration is profoundly depressed from 100-200 breaths per minute during activity to one breath every 5 minutes in deep torpor. In addition, they usually do not eat or drink for almost all of the hibernation period, but survive in a very low metabolic state by oxidizing their fat stores.
Backyard Biology is on a break until the end of August, but I highly recommend you visit the following website to enjoy the amazing photography of Grand Marais, MN photographer Paul Sundberg, as he chronicles life in a Robin’s nest from egg to fledging. What a treat!
As the worm turns…into baby birds.