Brown Teal Behaviour
It is mainly the behavioural features of Brown Teal, which set it apart from all other species of dabbling duck, and in a class of its own.
Brown teal have the unique and extraordinary tendency to hide in grass and overhanging vegetation for most of the day and whilst this behavior has been generally described as ‘crepuscular’ it is now felt more appropriate to describe it as ‘nocturnal’.
In 1921 Herbert Guthrie-Smith in his ‘classic’ book ‘TUTIRA’ was one of the first people to document the nocturnal behavior of Brown Teal, stating “There during the hours of light he (being Brown Teal) hides in the dense covert and in deep shade, only at night time venturing out, but then showing himself strangely tame and fearless”. Guthrie-Smith also witnessed the decline of Brown Teal at Tutira in Hawkes Bay and commented at that time “It is not improbable that with more covert (cover) and better feed the numbers of brown duck may again revive”. In the same section he mentioned “The value of the gamekeeper is still a conception quite beyond the mind of the New Zealander”. And so it remains today; some 80 years on!
There is growing evidence to support the preposition that Brown Teal became largely nocturnal because of the aerial threat from the Australasian Harrier (Circus approximans). Some researchers have suggested that this trait actually goes back to the period when New Zealand had its own Giant Eagle (Harpagornis moorei).
By contrast, a pinioned mated pair living on an open topped pond in an environment protected from ground predators, will spend much of their day on the open water. These birds do however, appear to have a sixth-sense when a harrier hawk is in the vicinity and they will rapidly head for cover.
Wild Brown Teal are incredibly active at night and spend hours searching in paddocks (fields) for worms and insects, or in estuaries for small shellfish. They also seem to mostly enjoy themselves dissecting patches of cow dung and also sieving endlessly in muddy pools. This trait is very obvious with captive teal and a muddy area in an aviary is a priority amongst captive breeders.
Outside the breeding season Brown Teal are highly gregarious, just like mallards, assembling in flocks at their traditional roost site. Where roost sites have been modified by man, or by nature, changes at the flock site have invariably lead to the decline of Brown Teal in that area. Unlike mallards Brown Teal do not adapt readily to change.
Another unique feature of Brown Teal is that when a pair bond has been established both male and female become the most vicious and murderous of all dabbling ducks. No other dabbling duck species display this feature, and this behavior is not apparent, to anywhere near the same degree, in either the Auckland or Campbell Island teal.
In the wild and in captivity Brown Teal are superior parents compared to all other dabbling ducks, with the male actively ‘educating’ and nurturing his progeny right through to the flying stage – and beyond. The degree of such male attentiveness is not found in any other species of dabbling duck.
Unlike most dabbling duck the pre-copulation behavior of Brown Teal is unique and simplicity itself; head-pumping prior to copulation sometimes occurs, as does inciting by the female. Some ‘head-up-tail-up’ displays have been observed, but this is a rare occurrence. Post-copulatory behavior is also uninspiring; a swim and wing-flap are the only two usual movements after copulation, but these movements are also unpredictable.
Nesting in the wild usually occurs in thick vegetation, well away from the roost, but close to water, and each pair defends its territory with vigour, just as they do in captivity.
Yet another unique feature is that in a captive situation there is no possibility of retaining more than one pair of Brown Teal in an enclosure, whether it is an aviary or a fenced open pond. Only on ponds of at least 0.2 hectare will a pair of Brown Teal tolerate other species of waterfowl.
In small areas not only will a pair of Brown Teal firstly kill all other Brown Teal they will then kill all other species of duck that dare to invade their territory. They have also been known to severely chastise both the NZ Paradise Shelduck (Tadorna variegata) and Black Swan (Cygnus atratus).
At the flock site progeny of the year will, however, live quite happily together over a period of several months and it is not until the onset of the breeding season that aggravation amongst each other actually commences.
It is generally believed that a successful breeding pair of wild Brown Teal are monogamous and even though a mated pair will flock with others after the moult a previously established pair will cement their pairing more strongly.
When all wild Brown Teal have moulted, and all birds are fully flighted, they become very mallard-like in their flocking programme and they make their way to their favourite flock site. It is at the flock site where pair bonds are re-established and new pairs created.
Access to the annual flock site seems to be a critical part of successful pairings and a flock site could well be vital to the very survival of wild Brown Teal.
Over the last fifty years such flock sites have been mainly in estuarine areas and mostly at the confluence of fresh and sea water, but historically, as can be seen in the distribution section, this was not always the case and Brown Teal were found in every pond, lake, swamp, river and major wetland in New Zealand.
As already discussed, Brown Teal are a gregarious bird which assemble annually at their traditional flock site to form relatively large flocks. Historically the flock site would have been at an expanse of fresh water – a large pond, lagoon or lake – not too far from the birds breeding territory. Today what few flock sites remain are in estuarine habitat, at the confluence of tidal creeks and the sea.
There is still much to learn about the use of flock sites by Brown Teal and in addition to eliminating predators it is believed that the flock sites may play and an intrinsic and critical role in the very survival of Brown Teal. It is therefore essential that Brown Teal flock sites are legally protected, protected from human involvement, where possible the habitat is enhanced and each flock site must have an intensive predator control programme in operation for an indefinite period of time. This is not only essential for paired birds but also for juvenile and non-breeding birds which often remain at the flock site – after it has been vacated by the potential breeding pairs.
The breeding habitat adjacent to flock sites must also be protected from predators, and where possible the habitat enhanced to support more breeding pairs; together with habitat being created for Brown Teal, along the lines of what has happened at the Mimiwhangata Farm Park, near Whangarei, where freshwater lagoons and swamps have been specifically created for Brown Teal.