Highlights from the latest issue
July 2020 | Vol. 162, issue 3
We’ve another bumper issue containing 34 full papers, six short communications, a Forum article and our regular book reviews.
Here, Editor in Chief, Dominic McCafferty, has selected four of his highlights.
- GEOGRAPHIC AND SEASONAL VARIATION
Latitudinal gradients in some, but not all, avian life history traits extend into the Arctic
Michaela Martin, Anna Drake, Christine A. Rock & David J. Green
Clutch size and nesting success tend to increase with latitude, whereas longevity and developmental periods may decrease with latitude, so the textbooks say. But these trends are based on interspecific comparisons of species breeding at tropical and temperate latitudes. However, in this remarkably wide geographical study Michaela Martin and colleagues compared the life history of only one species, the Yellow Warbler, breeding in arctic habitat at the northern extent of their range (68°N), with those breeding in temperate habitat (50°N), Canada. They also used data from more than 20 populations spanning 0–68°N to determine latitudinal trends from tropical to arctic habitats. Martin et al. observed latitudinal variation in some traits from tropical to arctic latitudes, but not a consistent shift from a slow to fast life history. They conclude that the expectation for a general shift in life history traits may be over‐simplified and suggest that multiple environmental factors influence and select for variation in life history.
- VOCALISATIONS AND ACOUSTICS
Using microphone arrays to investigate microhabitat selection by declining breeding birds
Jeffrey P. Ethier & David R. Wilson
Acoustic techniques are increasingly being used in avian research. In this study, Jeffrey Ethier and David Wilson aimed to identify the microhabitat associations of two common species in steep population decline in Labrador, Canada using microphone arrays. They were able to show that Boreal Chickadees select trees of greater diameter while Cape May Warblers exhibited no obvious microhabitat selection. Ethier and Wilson conclude that microphone arrays are an effective tool for identifying preferred microhabitat for some species and could be incorporated into future conservation strategies.
- SHORT COMMUNICATION | DISTURBANCE
Flight‐initiation response reflects short‐ and long‐term human visits to remote islets
Martin Thibault, Michael A. Weston, Andreas Ravache & Eric Vidal
Visits to remote islands provide unique opportunities to investigate how birds respond to humans. Martin Thibault and collaborators studied how the Brown Noddy responded to their visits to the Chesterfield Islands, a newly classified reserve in the Coral Sea Natural Park. Repeated measures of flight‐initiation distances (FIDs) at three sites and over time, showed that FIDs were short and that there was a small decrease in FIDs with increasing exposure to humans over a short timescale. Thibault et al. conclude that habituation to humans is not always benign and recommend that behavioural metrics such as these may assist managers to assess and mitigate risks to species of high conservation value.
- FORUM | ADAPTATION
Ornithologists often use novel ways of studying rare species. Tiziano Londei used the growing number of internet photographs of two species of fish eagles, along with field observation to examine their functional anatomy. Unlike other piscivorous eagles, Londei found that the Grey‐headed Fish Eagle and Lesser Fish Eagle are able to rotate the fourth toe to accompany the first toe in opposition of the second and third toes. This feature allows them to strongly grip and carry fish and appears to be a shared characteristic convergent with the independent evolution of this feature in the Osprey and some other species.
Yellow Warbler | Kelly Colgan Azar CC BY ND 2.0 Flickr
Boreal Chickadee | dfaulder CC BY 2.0 Flickr
Brown Noddy | Andy Wraithmell CC0 PD Flickr
Grey-headed [Lesser] Fish Eagle | Julie Edgley CC BY SA 4.0 Wikimedia Commons