Member notes from the field: David Millican
It’s early October, “springtime” in Namibia. This is not the cool Blacksburg spring to which I’m accustomed. This “springtime” is dry, dehydrating, and desiccating; the discovery of true damnation. The moisture evaporates off my tongue as if it were splashed on a frying pan, the last bit of medicine from your Nalgene. The thrush does not sit outside my window and call, for it too sees the futility in displaying in this heat. Nor does the sweet smell of flowers fill the air. A few sporadic trees are budding, leaving purple, yellow, and white carpets beneath their canopies; but most are waiting for the rains, which are still a couple months away. Until the rains come, the forest resembles a wooden boneyard, with withered skeletons in splintering splay. There is no green in the forest, only browns and tans, save those respites of purple petals.
Namibia has the meanest sun I’ve ever met. Wearing short sleeves means frying my arms like bacon, and wearing long sleeves means basting in my own juices. And I’m by no means the only one. Until the rain clouds arrive, every animal has one goal: seek shade. Steenbok cram behind bushes without awareness of personal space, while Kori Bustards mimic the thin snags they hide behind, squeezing into the narrowest bands of shadow. But when the rainy season arrives? Then things are different. Giant grey battalions invade the sky, climbing over the Waterberg Plateau to descend upon the baked landscape. When your watch hits 12:00 pm, as you’re wondering if you have enough fluids to last until sundown, those clouds blow in on your literal second wind. But until those shielding clouds return, the only sources of shade are small islands under bare, gnarled Vachellia, complete with all the thorns you could wish for.
Here in my final field season, I have returned to Otjiwarongo, Namibia to continue my research on the cavity-nesting bird community. I’ve returned earlier than usual this time, hoping to document breeding activity during this “springtime”, when the bravest, hardiest, or perhaps unluckiest birds decide to breed. For most species, the arrival of rain jump starts the breeding season. Rains help fuel vegetation growth and spur insect emergences that make Moses look like a pretty mean guy. As vertebrates seize on the plethora of food, the breeding season sweeps across the landscape, and the forest begins to bustle with activity. But not all species are willing to wait and to resist the “heat of the moment” (bad, I know). Woodpeckers begin excavating well ahead of the crowds. Owlets also begin scoping out prime real estate early, including some of the freshly excavated woodpecker apartments. Scimitarbills (Rhinopomastus cyanomelas), iridescent purple-plumed chatterboxes, also appear to be breeding. I had previously recorded Scimitarbills breeding later into the summer, which may be an indication that they are less choosy than other species in the neighborhood.
By beginning my work in August, four months earlier than in previous seasons, I hope to observe the nesting behaviors of early-breeding species who brave the heat. What species are breeding early? What types of cavities are they using? And how do their nest-site selections compare to those of late-breeding species? Are the prized summer cavities also favored by species in the spring, or do these birds utilize different cavities entirely?
Admittedly, the first few weeks were just as slow as they were blistering. When nothing was breeding in August, nest searching seemed like an endless slog. But two months later, with the hatching of my first clutch of pearl-spotted owlets, it is clear that the work has been worthwhile. Now, I just can’t decide if owlets are actually as adorable as they seem, or if I’m just happy for company. Either way, I’m intrigued by the company of this woodpecker cavity, and can’t help but to wonder who makes the better roommate?
When December finally comes to Namibia, the talk on everyone’s lips is rain. After many dry months, everyone is waiting for those first quenching drops to fall, fall, fall, to accumulate into ponds and to percolate into reservoirs, liberating thirsty seedlings from their casings. Herbivores look forward to fresh grasses, carnivores lick their lips for the approaching calving season, and an inundating smorgasbord of insects emerge to clip back the grasses and fill many stomachs. Meanwhile, many of my old feathered friends are dusting off their hard hats to begin another season of building and babies. For species in the arid landscape of Namibia, rains are literally a life or death situation. With them, new generations are able to grow and carry on in the footprints (or wingbeats?) of their parents. Without them, life quickly turns to loss.
My previous two field seasons saw opposite ends of the spectrum. When I first visited in 2015, Namibia was already suffering from the previous year’s drought, and nobody was ready to accept a repeat. By March little rain had fallen, and just when most were ready to give up hope, the rains finally came in April, filling dusty dams and alleviating the suffering of wildlife, livestock, and humans alike. At that point, however, it was too late for many birds to breed. The forests were already growing quiet, and spider webs began appearing over cavity entrances likes boards on vacant housing windows. Other than an early wave of activity in January, the season ended just as quickly as it had began.
During my second field season the rains came early and often. Showers in November turned into New Year’s deluges, as the impact of a full blown La Nina drenched the country. Barbets, starlings, tits, and sparrows were already going gangbuster by the time I arrived, and the research center’s resident hornbill had sealed herself into her cavity more than a month earlier than she had the previous year. One wave of breeding lead into a second, as searching for nestlings wore out my boots into early May. Swimming through waist-high grass that concealed the silent slinking of mambas, I couldn’t swing a pair of binoculars without finding a sparrow or barbet nest. As orb-weaving spiders became impossible to avoid, and grass seeds became permanently embedded in my socks, I found myself in awe of the forest’s metamorphosis, and the drastic difference a little (or quite a lot) of rain could bring.
Now in February of my third and final field season, prospects are bleak. After a few tantalizing torrents in December, the faucet has seemingly run dry. The landscape flaunts scant blades of grass, providing little for the hordes of armored crickets and other prey species that have chosen to remain dormant. The rains spurred an early wave of breeding: Acacia Pied-barbets (Tricholaema leucomelas), Cape Glossy Starlings (Lamprotornis nitens), and Yellow-billed Hornbills (Tockus leucomelas) began despite the slow start. But unless good rains continue, these species will likely be finished breeding for the season. Some species may not breed at all. Of the three resident hornbill species, two of them, the Damara (Tockus damarensis) and Monteiro’s (Tockus monteiri) depend on the rains and the crickets they bring. Yellow-billed Hornbills are willing to make the gamble, nesting at the first signs of rain in November and December. hoping for good rains to bring the necessary food to support their nestlings, and potentially to facilitate a second clutch later in the season. And if the rains do not come, and the food remains scarce, at least there is still the hope that one chick will fledge the nest. But for the later-breeding Damara and Monteiro’s hornbills, gambling does not appear to be an option. These two species will not breed where there is not rain. Whether they move to areas with better rain or simply opt not to breed is unknown, but by the looks of the few pairs still displaying around the landscape, my best guess is that many will have to skip this year, likely as they did the year before.
more to come…
Guest post by:
Ph.D. Candidate and Interfaces of Global Change Fellow
Department of Biological Sciences
Virginia Polytechnic Institute and State University
4096 Derring Hall, Blacksburg, VA 24061
Would you like to share your research on the AFO blog? If so, send an email to firstname.lastname@example.org, and we’ll get your work featured on the website!