The art of the Teal

The life of teal is a life on the wing. It is the smallest dabbling duck in the Boreal zone, but in terms of migration it covers huge distances from breeding waters to the non-breeding areas far, far away. The same bird can spend time in an oligotrophic lake in Russia during breeding, a brackish Baltic Sea lagoon or a tidal mudflat in the Atlantic coast during autumn, and a rich river delta in the Mediterranean in winter – and some individuals even straddle over into North Africa for a dabble. It takes a lot of adaptability to switch between such vastly different habitats, and at the same time avoid becoming dinner of arial predators and human hunters.

This book – The Teal by Matthieu Guillemain and Johan Elmberg published in 2014 – is part of a long tradition of monographs in ornithology, and a must for everyone with love for ducks. It’s clear from the writing that the authors hold their study species dear, and each part of the annual cycle is covered in well-written informative chapters.

Because of hunting, ducks have long been a focus of research and there’s a huge body of literature on many aspects of duck ecology. However, it is not easy accessible, either because it is old, or that it has been published in journals with a narrow scope. Here the authors have done a massive job to summarize tons of hard-to-get information in text, as well as tables and appendixes. Although most readers will not spend too much time on the appendixes, they serve as reference when you need it. For instance, if you want to know the helminth fauna detected in Teal, you can peruse appendix 8 – a full 7 pages of wormy stuff, or for a list of food items turn to appendix 6.

Although the book is written in the scientific tradition and heavily referenced, it is still a fairly easy read with clear chapter distinctions and a number of boxes for specific questions. You get to know both the Eurasian Teal and the North American sister species Green-winged Teal – which are extremely similar in apperance and ecology, but with rather different research history. The book devotes one chapter to distribution and numbers, one to  movements and migrations, one to foraging and diet and one to breeding ecology. From there the book turns to mortality, demography, harvesting and conservation, before ending in a list of priorities for future research.

The teal is facinating bird and The Teal is a very good book. When reading it, it struck me how much I have yet to learn even though I have studied ducks professionally for several years. My main study species is the mallard, which although bigger and not as migratory share many traits with the teal, and knowledge presented in this book is valuable for all dabbling ducks. My largest knowledge gaps was the breeding and foraging ecology parts, and I am grateful for filling those by reading the book. But there are so many other aspects of teals that are facinating, including the apperant ease of long-distance migration despite generally not putting on large food reserves, or the intricate pair forming and sex life of ducks – and the very large hunting bags and their impact on population demography and numbers.

Thus, this book fills two purposes: as a general read for anyone interested in ducks, and a specialized reference book for researchers. It was published in 2014 and if you haven’t bought it yet, you should. Especially, I think this book is an essential read if you’re into avian influenza, to widen the horizon of the ecology of one of the virus’ main hosts. An increased understanding on the life history of dabbling ducks would go a long way to clear some misunderstandings that the field is laden with.

A pair of American Wigeons are about to land next to a pair of Eurasian Wigeons and mr and mrs Green-winged Teals.

Fly little duck, fly – or else …

By Jonas Waldenström

“Bam-bam, bam-bam”!!!

A week ago, this year’s duck hunting season started. Or harvesting, as some hunters would say. And it is really a harvest: it is estimated that around 180,000 Mallards are shot in Sweden alone. This in a country with only 10 million inhabitants. On top of that you may add Eurasian Teals and diving ducks such as Tufted Ducks. And the occasional Garganey, Gadwall and other more rare species – collateral damage in the cannonade.

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Should we worry? Should we be angry? No, at least not today, and at least not in NW Europe. The image of a hunter as a trigger-happy mooron isn’t accurate – actually many hunters are conservationists. Biodiversity doesn’t come from nothing, it requires landowners that preserve or maintain land. In this case good breeding and stopover areas for ducks.  Without the incentive for hunting, a lot of nice duck habitat wouldn’t exist today. And you can combine bird watching and bird hunting, two sides of the same coin.

On the other hand, hunting has consequences. For the individual (a dead duck can not reproduce) and for the population. Our data from Ottenby show that roughly 10 % of the Mallards we equip with a band will be shot. With a migratory species, a population that is breeding in some part of Europe may be harvested in another region. In our case, a fair proportion of the Mallards shot in E Sweden originate from Finland, Russia and the Baltic states and may continue migration to Denmark, Germany and the Netherlands. Each country with their sets of riffles.

For Mallards, it has been shown that hunting is not an additive mortality, but a compensated mortality at the population level. In other words, the death toll imposed by hunting reduces the population number, but this is in turn compensated by less mortality from other sources, or by higher breeding output of the remaining birds. Density-dependent population regulation, you can say.

It should be noted, as well, that a chunk of what is shot is released Mallards. You know the put-and-take industry in recreational fishing? This is something similar: estates where Mallards are breed and released, and where visiting hunters pay for hunting. Roughly 100,000 ducks in Sweden per year, and more than a million in France! Per year! Some of the domestic origin birds survive the onslaught and live to reproduce. As they have a different stock than wild Mallards, some researchers fear that they could affect the population genetic structure of Mallards in Europe. Some things can be observed already today: Mallards tend to be heavier now than 40 years ago, and have fewer lamellae in the upper mandible, presumably an adaption to a more coarse diet. Whether this really has to do with released ducks isn’t settled yet, but similar trends are not seen in Eurasian Teals – a species not reared for hunting purposes.

But one thing is clear: the start of the hunting season is also a major push for birds to start migrate in earnest. Especially evident is the movements of Eurasian Teals which tend to start the same morning as the hunting season starts. But, little ducky, you may run, but you can’t hide – hunting will continue along the migratory route and on the win