Helicopter Parent

As the most literal of helicopter parents, a ruby-throated hummingbird mom (RTH, Archilochus colubris) takes hovering to a whole new competitive level.

In the case of this feathered sprite (2.8 – 3.5″ long, including bill, and just over 1/10 of an ounce), though, the word “hover” has more to do with the ability to fly than with over-protective child rearing. Which is not to suggest that an RTH mom is neglectful. Far from it… she’s just a bit Type A.

Both male and female RTHs winter in Central America or along the southern tip of Florida, but from the moment a gal returns to her summer stomping grounds in the eastern half of the US or southern Canada, she’s all go-go-go… because her biological clock is ticking like a stopwatch.

Barely hesitating to catch her breath, the first order of business is to find a baby daddy. She’s not looking for ever-after; Mr. Right-for-Now will do as long as he’s strong and handsome. Since the males of her clan aren’t the slightest bit interested in becoming a Mr. Mom this arrangement suits everyone just fine. With barely a look backward by either party following their four-second assignation, he jets off to find another hookup, and she speeds away to shop for flower-down to line the bassinet.

It takes about six days for this mom-to-be to fashion a nest barely wide enough to hold a bottle cap, and tether it to a foundation with strands of spider silk. RTH nests are most often built on a tree branch but unusual alternatives, including loops of chain or extension cord, have proven acceptable in a pinch. Darting back and forth, the female will weave bud scales, lichen, hair or fur, and other creatively repurposed found objects into a cup-shaped cradle. Next, she’ll adorn the nest with lichen and moss, finally lining the interior with a soft, insulating layer.

Once the nursery has been prepared and decorated, 1-3 eggs the size of your pinkie fingernail will appear, and then… a pregnant pause.

Think about it. The longest stretch this single mother ever sits down, during her entire life, is to incubate a clutch of future hummers. Imagine, if you will, the kind of patience, willpower, and elevated estrogen levels it takes for a creature who has lived on the wing, perpetually flitting hither and yon since leaving her own natal nest, to STOP…  settle in… and then just…

……………………sit…

…………………………..for 12-14…..

……………………………………………..long…..

………………………………………………………….idle…..

……………………………………………………………………..days.

During this time, the newly stationary creature will leave her nest only for brief breaks to stretch or grab a bite to eat. She’ll anchor there, day and night, rain or shine. No baby shower, no friends stopping by to say hello; they’re all brooding their own nest eggs. No television, even though this would be a great time to binge watch David Attenborough’s The Life of Birds. No smartphone at the ready to check email, take selfies, and whine to everyone on Facebook that she is bored beyond reason.

Heck, when I manage to stop and meditate for ten minutes two days in a row I feel like a Zen Master.

Once the chicks hatch it’s back to her normal hyperactive life… and then some. RTH nestlings are naked and wobbly-headed, with an appetite that dwarfs their bitty bodies. For the next few weeks, Mom will need to make 1-3 grocery runs per hour,  from dawn to dusk, regurgitating the food she’s foraged and hauled home in her belly into the beseeching beak of each precious child.

Once the babes fledge at 18-22 days old they’ll disperse among the branches… not too far away from the nest or each other initially, but spaced out enough to make dinner deliveries much less efficient for their harried mother. As the kids grow stronger and bolder, they’ll spread out further, testing their own wings… and Mom’s ability to be everywhere all at once.

Oh, and somewhere in that frantic schedule, this solo parent also needs to down enough calories to keep her own metabolism running on all cylinders.

Luckily, she flies like a super-charged, hyper fuel-efficient, über-nimble helicopter. Hummingbirds have been known to reach speeds of nearly 35 mph (55 kph), which is certainly impressive. Not record-breaking among the avian set, though. The difference is that most of the planet’s fastest feathered fliers reach their top speeds in a dive, asking gravity to add a significant boost to their velocity. Acrobatic RTHs can fly straight and fast, too, but it’s their ability to achieve what those avian missiles can’t—a true hover—that sets them apart.

This isn’t using a thermal to save energy, like vultures, ravens, petrels, and other long-winged birds do. That’s soaring. Hummingbirds move their wings in a figure-eight pattern at over 50 beats per second, allowing them to stop on a dime or adjust their position up, down, forward, or backward. That frenetic rhythm is also creates the humming noise that’s the source of their common name.

It also helps that the lady’s jet fuel of choice is syrup. Flower nectar, to be more precise, accounts for approximately 90% of an adult hummingbird’s daily caloric intake. RTHs and other hummers have a large surface-area:body-mass ratio, which means they lose a lot of heat in the normal course of living. Plus, their metabolism is so high they have to enter a torpor once a day, between sunset and sunrise, just to make it through the night without having to recharge.

Unlike the sugar-water mixtures backyard bird enthusiasts cook up to fill hanging feeders, blossom juice consists of more than just sucrose (from which plain white table sugar is derived). Flowers also produce fructose and glucose, as well as amino acids, antioxidants, calcium and other trace minerals, lipids, phosphates, and some protein. Other sources of protein include insects that have found their way inside the flower’s throat, where they are slurped up along with the nectar. Hummingbirds will also glean aphids from plants, pluck spiders from their webs, and nab flying insects mid-air. During breeding season, female RTHs spend a lot of time catching insects because nestlings need a high protein diet to grow and develop properly. Once they mature they’ll gradually switch to the high-carb diet of an adult.

As befits a fast-paced life, in barely the blink of an eye (or the wing-beat of a hummingbird) summer is over. Male RTHs often head south first, in early August. Females tend to delay departure until late August or sometime in September. After months of feeding others—our feathered Supermom may have raised as many as three broods in a single season—the time has come to focus on self-care, and on building enough fat reserves to power through an 18-22 hour non-stop flight across the Gulf of Mexico.

The last of her children have left the nest and are, hopefully, ready for their first migration. RTHs are solitary migrators so Mom’s helicopter parenting days are over… until next year.

Because a mother’s work is never really done.


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© 2019 Next-Door Nature. no reprints without written permission from the author (I’d love for you to share my work–just ask first). Thanks to these photographers for making their work available through a Creative Commons license (from top to bottom): Dan Pancamo, Steve Rider, TCDavis, BudOhio, ssemone, BudOhio, and Henry T. McLin.

Hot and cold

next-door nature, urban wildlife, fence lizard

Everyone, even fence lizards and other ectothermic creatures, are feeling the heat these days (Photo: Bandelier National Monument, Creative Commons license)

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Temperatures across the southern half of the U.S. are soaring into triple digits, so I was trying to think of creative solutions to beat the heat when it hit me—why not become cold-blooded!

next-door nature, urban wildlife, fox squirrelAlas, my brain must have overheated. Once air conditioning allowed a cooler head to prevail I realized that what seemed like a brilliant idea while baking beneath a blazing sun is absolutely, completely, utterly impossible… and not simply because mammals cannot will themselves to undergo metamorphosis.

You see, technically there’s no such thing as a cold-blooded animal (unless you’re speaking metaphorically about someone who lacks emotion or empathy).  Or a warm-blooded animal, for that matter. Both terms are shorthand for the ways in which body temperature (aka thermophysiology) is controlled in different types of organisms.

Most mammals and birds are classified as endotherms (Greek: endon = within; thermē = heat). For these critters thermoregulation is an inside job, primarily by way of metabolic processes. Under extreme environmental next-door nature, urban wildlife, sunbathersconditions some physical mechanisms come into play, but not solar energy (at least, not directly). If the mercury plummets and the body’s core temperature begins to drop, muscles shiver to create warmth; if the core temperature starts to rise the body perspires to cool via evaporation. No sweat glands? Pant like a dog… or birds. All evidence to the contrary, since humans are mammals, swimsuit-clad sunbathers dozing in rows on a beach or poolside with icy drinks standing at the ready are, in fact, capable of maintaining a relatively constant body temperature.

next-door nature, urban wildlife, gray treefrogWhen an animal’s body temperature is strongly influenced by ambient conditions it’s an ectotherm (Greek: ektós = outside). Fish, amphibians, reptiles, and invertebrates rely on external heat sources to get their juices flowing, especially during the chillier seasons or cooler times of day. That’s why these animals can be seen basking on rocks, roads, and any other warmth-radiating surface. Then, when they can’t stand the heat they get out of the kitchen, retreating into shade, water, or underground to cool off (Sound familiar? We really are more alike than different).

Take-home message: mammals and birds are endotherms; invertebrates, fish, amphibians, and reptiles are ectotherms.

Except when they aren’t.

It’s the exceptions that make the rule, right? Let’s begin with the usual ectotherm suspects. According to one source, 2% of invertebrates are endothermic. Regrettably, the informant failed to name names but, in spite of the fact that spineless animals are not my strong suit, I did managed to chased one down—snails and slugs (Oops, that’s two… and “chased” may be overstating things).  Fish, being vertebrate species, are my regular beat so I can state with certainty that billfish (e.g., sailfish, marlins), tuna (Scombridae), one family of sharks (Lamnidae, including makos and whites), and one species of mackerel (Gasterochisma melampus) are endothermic… at least to some degree. I’ve yet to find a reliable report of an endothermic amphibian, but among the reptiles sea turtles exhibit both ecto- and endothermic traits.

next-door nature, urban wildlife, echidnaMoving along to the endothermic exceptions… Hummingbirds (Trochilidae), swifts (Apodidae), and common poorwills (Phalaenoptilus nuttallii) all experience periods of lower body temperature and metabolic rate; therefore, some biologists argue they have ectothermic traits. Additionally, there are mammals—certain rodents, a couple of lemurs, and many bats—that enter hibernation or estivation in response to low temperatures or drought, respectively. Then there’s the echnidna (Tachyglossidae), a “primitive” mammal from Australia that’s an ectotherm eleven months of the year and an endotherm during the month when it lays its eggs (Yes, eggs. If you like rule-breakers Australia is your Mecca. In the interest of time and space, though, we’ll have to save monotremes for another day).

What I’ve presented above is a fairly simplistic description of thermophysiology.  Why stop there? Because a more thorough treatment would require a good deal of nuance and a complicated discussion of sub-categories, not to mention a stiff drink (the current temperature is 99°F and rising—make mine a frozen margarita).  But since it’s so hot I’ll go ahead and venture past a toe in the water… up to my knees, but no further.

next-door nature, urban wildlife, elephant shrewOne subset of the endotherms are tachymetabolic (Greek: tachy = quick), organisms with a consistent and extremely high metabolic rate. Shrews (Soricidae) are a perfect example—diminutive beings with massive appetites, their metabolic rate is at least five times that of similarly sized ectotherms. Being able to snack non-stop and still rock a bikini probably sounds too good to be true. It is. Finding a constant supply of calories without access to fast food and grocery stores is no picnic. Bradymetabolic (Greek: brady = slow), which could easily be mistaken for bipolar disorder, is no bed of roses either. These organisms swing wildly between a high (when active) and low (when resting) metabolism, usually based on either external temperatures or food availability. (If you think someone else has got it better, rest assured you probably don’t know the whole story.)

As biologists refine our understanding of how bodies work, language evolves and once popular terms like cold-blooded fall from favor. Popular stereotypes suggest otherwise, but scientists are not completely immune to trends. When I was an undergrad, for example, the preferred word for organisms influenced by changes in ambient temperature was poikilotherm (Greek: poikilo = varied, irregular). Although still useful for making distinctions between types of ecotherms, the term is used less frequently now and may be on it the way out.

next-door nature, urban wildlife, crocodilesC’est la vie. Styles change, in both the lab and on the beach (Thankfully. I’m old enough to remember when Speedos were all the rage in men’s swimwear). I’d be willing to bet, though, that most Earthlings won’t give up sun worship any time soon. Chillin’ in a sunbeam feels too good, whether you need it or not (at least as long as there’s a pool nearby).

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© 2012 Next-Door Nature—no reprints without written permission from the author (I’d love for you to share my work. Just ask first.). Thanks to these photographers for making their work available through a Creative Commons license: Bandelier National Monument (sunning fence lizard); Michael V. Flores (fox squirrel cooling down); Nick Papakyriazis (sunbathers); geopungo (gray treefrog); BohemianDolls (elephant shrew); and Jess Loughborough (basking crocodiles).