news & views bigger&bigger feeling The largest extinct giant of all? chirpy Victorian-era taxonomists scrambled to A. maximus turned out to belong not only demonstrate their own status as an au- to a new species, but also a new genus. The thority on newly discovered extinct taxa. authors named it Vorombe, a Malagasy ver the past few decades, nu- After a deluge of descriptions in the 1890s word meaning ‘big ’. As this was the merous studies have shown and a handful in the early 20th century, species originally named A. titan in 1894, that noise pollution from traf- no fewer than 15 species of it duly became Vorombe titan. Moreover, ficO can have an impact on and had been described. Confusion reigned. Andrews’ assertion that this was the larg- other wildlife. The most obvious effect One species described during the diz- est elephant bird has finally been vindicat- on birds is a change in song structure to zying 1890s was A. titan, which Charles ed: the estimated average mass of Vorombe communicate in a noisy environment, Andrews argued was the largest of the is 650 kilograms, with some individuals as but more insidious impacts include al- maximus skeleton CREATIVE COMMONS elephant birds. But A. titan subsequently heavy as 730 kilograms (and in the case tered habitat use, increased stress lev- or most of the past 170 years Aepy- lost its species status and was incorporat- of one tantalisingly incomplete specimen, els, decreased foraging efficiency and ornis maximus, the largest of Mad- ed within A. maximus. possibly 860 kilograms). even reduced chick growth rates and agascar’s elephant birds with an For the new elephant bird study, James The (re-)discovery of this truly enor- breeding success. Festimated average body mass of 450 kilo- Hansford and Samuel Turvey examined mous elephant bird means that this fam- The best evidence for these impacts grams, was considered the heaviest avian and painstakingly measured 346 bone ily’s claim to including the largest avian comes from experiments designed to species ever to have walked the earth. specimens from museums in Madagas- species known to have existed on earth tease apart the impacts of noise from However, in 2016 evidence emerged that car, Europe and North America. They is secure, at least for now. Like other other potentially confounding vari- A. maximus might not be the largest ex- used cutting-edge multivariate analyses members of its family, Vorombe seems to ables associated with human-modified duncan butchart tinct bird after all. The authors of a paper to identify clusters of morphologically have occurred primarily in the semi-arid habitats. Such experiments typically the lockdown were similar to those in A pair of Fiscal Flycatchers duetting. In urban on mirihungs, a lineage of gigantic goose similar remains and, crucially, incorpo- south-west of Madagascar. While much can only be conducted at a very small the mid-1950s! settings, songbirds sing louder, simpler songs relatives that existed in Australia until rated statistical techniques that account remains to be learned about this avian scale in space and time, but the Covid- The sparrows responded to the re- to be heard over the constant, pervasive approximately 50 000 years ago, estimat- for size variation within species, includ- giant, just knowing that such a behemoth 19 pandemic created a vast natural ex- duced traffic noise by singing more traffic drone. ed average body masses for female and ing sexual dimorphism. Their analysis, roamed this biologically remarkable is- periment. An elegant study by Eliza­beth softly, yet their songs were audible at male Dromornis stirtoni of 450 and 530 published in 2018, suggests there were in land deepens the intrigue surrounding Derryberry and colleagues published roughly twice the distance than dur- means that urban sparrows should rap- kilograms respectively. fact just four elephant bird species, down the creatures that used to inhabit it. in Science (370: 575–579) shows how ing ‘normal’ traffic conditions. This ex- idly switch to more complex songs in While the mirihung paper was being from 15 recognised in the early 1900s ANDREW McKECHNIE White-crowned Sparrows around San plains why many birders reported that the absence of traffic noise; as expected, published, however, two UK-based re- and seven more recently. Now two spe- Francisco altered their songs in response their garden birds were singing more the urban sparrows greatly extended searchers were working on the first taxo- cies belong to the genus Aepyornis and Reference to the lockdown. loudly during the Covid lockdown (see the frequency range of their trills dur- nomic reassessment of elephant birds in one to Mullerornis, the smallest of the Hansford JP and Turvey ST. 2018. ‘Unexpected The study compared male sparrow African Birdlife 8(5): 20‒23). Given the ing lockdown. more than half a century. The first de- elephant birds. diversity within the extinct elephant birds songs during the lockdown with those inverse square rule, a doubling in song Greater communication distances scription of elephant birds in western sci- The study’s most unexpected result, (Aves: Aepyornithidae) and a new identity for in the same areas in previous years. In transmission distance means that birds and increased information content in entific literature in 1851 preluded a flurry however, involved the fourth species. Sev- the world’s largest bird.’ Royal Society Open 2015 and 2016, sparrows in urban areas (and birders) would hear four times as male song most probably reduce terri- of species descriptions as competitive eral of the largest specimens thought to be Science 5: 181295. experienced background noise levels many sparrows during lockdown. torial conflicts, decreasing stress levels nearly three times louder than their Prior to lockdown, the songs of ur- and increasing the energy available for rural cousins and sang more loudly to ban male sparrows had a narrower other activities such as breeding. The Just want to check…? Use the new magazine archive! compensate for the noisy soundscape. frequency range than rural males to study suggests that birds readily adapt During the lockdown in April‒May reduce overlap with the low-frequency to noise pollution and can revert rap- lanning a trip to the Overberg and want to check our article on De Mond? Or 2020, background noise levels dropped traffic drone. However, experiments idly to ‘normal’ if the noise is removed. Ptrying to decide on your next birding destination in Africa – Ethiopia or Ghana, in both habitats, but much more so in have shown that sparrows assess the fit- However, it also indicates the subtle Uganda or Kenya? And you know we ran an article on identifying cisticolas, but urban areas, to the point that there was ness of other males by the rate and fre- and often complex impacts of sound which issue was it in? no difference between urban and rural quency range of their trilled notes. The pollution on birds, a topic that is of- Now help is just a click away: simply go to www.birdlife.org.za/african-birdlife- sites. Based on the number of vehicles faster the trill and the greater the fre- ten overlooked compared to the many index/ and you’ll find six years’ worth of African Birdlife articles from the first issue (November/December 2012) right up to the end of 2018 – it couldn’t be easier! crossing the Golden Gate Bridge, traf- quency range of each note in the trill, more overt human impacts on birds. fic levels in San Francisco at the peak of the more intimidating the male. This PETER RYAN

12 african birdlife january/february 2021 news & views 13