By Bill Bateman. Hans Christian Cornelius Mortensen, back in the late 1890s, made small bands of aluminium, marked with his name and address, and attached them to the legs of birds – from starlings through to storks. Since then, bird ringing (in the UK and some other parts of the world, such as South Africa) or bird banding (here in Australia and also the USA), has become a mainstay of ornithological research. Every year, around the world, thousands of birds are banded with small metal bands that identify them as individuals. Speaking personally, it is also great fun – setting up mist nets in the pre-dawn darkness, carefully extracting the birds, fixing tiny, bright bands to their fragile legs. In South Africa we had to share a water hole with a determined white rhino, which eventually urinated all over the net in a territorial fury. For bigger birds, like seabirds, you can be in the midst of a noisy colony of terns or noddies: at Lancelin Island in Western Australia we could literally grab birds off their nests to band them.
For birds of prey you can use a bal-chatri trap, where a mouse is used as bait in a box covered with loops of fine mesh to trap the bird’s feet (the mouse survives to bait another day) – you cannot do this in Australia however, where it is illegal to use live vertebrate prey.
Amongst other things, we learn about bird longevity: that albatrosses are long-lived was suspected, but thanks to bird banding we know that ‘Wisdom’, a Laysan Albatross (Phoebastria immutabilis) is now 65 years and still breeding (Jimenez-Uzcategui et al. 2016). More modest records include ten year old Mountain Chickadees (Poecile gambeli) and eight year old Lincoln’s Sparrows (Melospiza lincolnii) (Rowan et al. 2014). We also learn – and this will become ever more important as we continue to change the world around us – about long-term and large scale changes in population sizes and movement patterns of many species of birds (Thorup et al. 2014).
We make the assumption when we band birds that we are only putting them through a minor inconvenience, and that handling and banding is safe for them (Calvo & Furness 1992, Spotswood et al 2012). This is not always the case: Griesser et al (2012) found that plastic colour bands (used along with metal bands to identify individuals from a distance) can cause inflammation to the legs, or even open slightly and trap the feet of some small bird species.
The image below shows the leg of a Marsh Tit (Poecile palustris) whose colour band caught on a blackthorn thorn, leading to the bird’s death (Broughton 2015).
This is a worry – is it common? Broughton (2015) recorded equally low incidence of permanent injuries in both banded and unbanded Marsh Tits, but slightly higher foot damage (1.5% vs 0.2%) in banded birds (404 banded birds over 12 years). The damage came from colour bands, not the metal bands: this percentage seems low, and probably means that we do not have to worry as long as we are careful about how many rings we put on birds. However, field scientists face the constant ethical issue that much of what they do may disturb or distress the animal they work on: although the potential benefits of long-term research such as banding programs can provide us with valuable conservation data it behoves us to be aware of ethical issues, and to do our best to ensure that we eliminate or minimise them.
- Calvo, B. and R.W. Furness (1992), A review of the use and the effects of marks and devices on birds. Ringing & Migration 13(3): p. 129-151.
- Spotswood, E.N., et al., (2012) How safe is mist netting? Evaluating the risk of injury and mortality to birds. Methods in Ecology and Evolution,3(1): p. 29-38.
- Griesser, M., et al., (2012) Causes of ring-related leg injuries in birds–evidence and recommendations from four field studies. PloS one 7(12): p. e51891.
- Broughton, R.K. (2015), Low incidence of leg and foot injuries in colour-ringed Marsh Tits Poecile palustris. Ringing & Migration, 30(1): p. 37-42.
- Jimenez-Uzcategui, G., et al. (2016). Longevity records for the waved albatross Phoebastria irrorata. Marine Ornithology, 44(2), 133-134.
- Rowan et al. (2014). North American longevity records for nine landbird species monitored at Yosemite National Park’s MAPS stations. North American Bird Bander, 39(4).
- Thorup, K., Korner‐Nievergelt, F., Cohen, E. B., & Baillie, S. R. (2014). Large‐scale spatial analysis of ringing and re‐encounter data to infer movement patterns: A review including methodological perspectives. Methods in Ecology and Evolution, 5(12), 1337-1350