Week 3: Screamers to Diving Ducks

Day 9: Northern screamer – Chauna chavaria

Ear defenders needed

Although it looks more like a leggy pheasant, this is the first representative of the Anseriformes (‘goose-shape’) that I measured. This is surprising because, of the 150 anseriform species, this is one of three species that is not a swan, duck or goose. The three screamer species occupy their own family, the Anhimidae. This is a classic example of what revelations DNA can produce. In appearance it is not ‘goose-shaped’ at all and was originally placed in the Galliformes however DNA sequencing showed that they were more closely related to ducks and geese. Their closest relative is the Australian magpie-goose which has its own family: the Anseranatidae. All other members of the order are in the family Anatidae.

The three screamers are certainly unusual birds. One of the first things I noticed when measuring them (besides their terrible condition) was two extremely sharp, inch long spurs on each wing which are used in territorial disputes. I had already encountered sharp spurs on the legs of male galliforms but in the screamers they are found in both sexes. Their name refers to their wailing alarm calls which deter would-be predators and apparently this makes them good guard dogs! The northern, or black-necked screamer is the rarest, inhabiting open, marshy areas in northern South America.

Day 10: Bewick’s swan – Cygnus columbianus bewickii

Memorable face

The Bewick’s swan is the Palaearctic subspecies of the tundra swan, the smallest Holarctic swan. Its Nearctic neighbour is the whistling swan (C. c. columbianus). I almost chose to write about its large cousin the whooper swan (C. cygnus) but the Bewicks clinched it in terms of historical and personal importance.

Like many members of the Anatidae, tundra swans migrate south during the winter from their breeding grounds in the Arctic and subarctic tundra. There they take advantage of the burst of foliage that carpets the ground in the summer where the days become endless and plants absorb the sun’s rays. The Bewick’s swans come to us all the way from Western Siberia and they arrive in England in mid-October.

They are a historically important species because of their role in the Wildfowl and Wetlands Trust. The WWT was founded in 1946 by Sir Peter Scott, the ornithologist and artist who was encouraged to value wildlife from a young age by his Antarctic explorer father, Captain Scott. WWT Slimbridge was set up at the same time to help study and conserve British wildfowl. The WWT has grown massively to nine reserves with a million visitors per year and two Bewick’s crest its logo.

At Slimbridge, Scott realised that every Bewick’s swan had a unique pattern of yellow and black on its bill so that each individual could be identified year on year. This started one of the longest-running single species studies in the world. It is important to monitor these birds as their population has plunged since the 90’s and the WWT endeavours to discover and prevent threats to the swans in the UK and abroad. X-rays reveal the damage of illegal shooting and GPS trackers are now showing their migratory routes. Among the regulars to return to Slimbridge each year is Crinkly, the swan with the unfortunate kinks in his neck.

Bewick’s swans and Slimbridge are of great sentimental value to me. When I was young I used to go to Slimbridge with my family where my sister and I would feed the abundance of captive species from around the world. No doubt I would have seen the Siberian swans trumpeting away! However, aged 15, I decided I had to acknowledge them as a young adult so another trip to Slimbridge was needed to see these beautiful birds again. Now Slimbridge’s appeal for me is the hides which overlook the flood plains of the Severn, attracting thousands of waterfowl and waders. In addition, the WWT are bringing cranes to the area which I must go and see soon! 

Day 11: Northern shoveler – Anas clypeata

Aquatic herbs? I dabble

Choosing which ducks to talk about has been challenging because I am fond of so many of them. However I decided I would try to represent the family as well as possible. The Anatidae comprises about ten subfamilies of which I will include members from the swans and geese (Anserinae), the dabbling ducks (Anatinae), the diving ducks (Aythyinae) and the sea ducks (Merginae).

The shoveler is a dabbling duck which demonstrates many of the important traits of the group. Its large flattened bill contains lamellae which filter water as it is pumped through. Dabbling ducks are herbivores which can be seen upending in the water to reach vegetation in shallow pools and marshes. Shovelers stand out among the dabblers for their unusually large, flat bills which gave them their old genus name Spatula. They are able to use their bill to sieve the water for freshwater invertebrates in addition to standard dabbler food.

Dabbling ducks have not adapted to water as strongly as their diving counterparts and cannot get far below the surface however they are strong fliers, able to take off vertically from the water when spooked and many are seasonal migrants, returning to British wetlands in the winter. Dabbling ducks, and ducks in general, hove notable sexual dimorphism. Females are generally drab and brown whilst males sport a variety of colours as well as unusual feather shapes (like the curly tail of a mallard). The attractive plumage of males is lost during their summer moult after the breeding season when they come to resemble the females. This is known as their eclipse plumage.

The shoveler is part of an assemblage of ducks that can be seen around wetlands in winter. Near to my house in Dorset I often go out on crisp winter days to reed beds (Radipole, Ham Wall) and estuaries (Arne, Brownsea, Steart) to see the abundant duck species. I am always amused at how predictable it is to see a large flock of wigeon (Anas penelope) occupying the centre whilst several teal (Anas crecca) dabble on the periphery. A few shovelers sweep the water with one or two pairs of gadwall (Anas strepara) upending in amongst them all. It is one of my favourite things to do over the Christmas season! My new patch includes the reservoirs at Tring which provide mixed depth lagoons suiting many different species. Dabbling ducks are joined by diving ducks in deeper water which I will discuss next.

Day 12: Red-crested pochard – Netta rufina

Handsome in ginger

The red-crested pochard is a member of the Aythyinae – the diving ducks. They are characterised by the ability to dive underwater where they can reach aquatic vegetation that the dabbling ducks cannot reach. In order to adapt to this lifestyle they have evolved larger feet which they use to propel them through the water. As a result of a more aquatic existence they have lost some of their flying ability and cannot take-off vertically, instead they can escape predators by diving away under the water.

Diving ducks are distinguishable from sea ducks (which also dive) mostly based on habitat. It is a good rule of thumb that a duck diving in a freshwater lake or reservoir is a diving duck (or grebe!) however the closer to the coast you are, the more likely you are to get sea duck species such as goldeneye (Bucephala clangula). If in doubt, sea ducks tend to look more unusual, especially in bill shape.

Rather than choose the more common tufted duck (Aythya fuligula) or pochard (Aythya ferina) I chose the red-crested pochard because I saw it wild for the first time just last weekend. On my first visit to the reservoirs around Tring I saw four pairs of this large diving duck and the males were especially handsome with their large orange heads ad pink bills. Only a few pairs breed in the UK each year, mainly in central England. The rest, around 300 individuals, visit lowland lakes in winter. Their status as British birds is confused by the fact that many individuals are escapees or deliberately released birds from private collections which are joined occasionally by wild birds from the continent. This reflects a common trend in water fowl as exotic ducks are often kept in captivity leading to many escapes and breeding attempts as well as the odd ‘rare sighting’.

Week 2: Grouse to Pheasants

Day 5: Caucasian grouse - Lyrurus mlokosiewiczi

Lord of the lek

We are now firmly in amongst the wild fowl in the family Phasianidae. Many of these species we know as game-birds and they have fed people around the world for thousands of years. As such they are well represented in the museum collection. This group of birds is typified by its dimorphism as gaudy males strut and compete for female attention. The Caucasian grouse is no exception. Closely related to the British black grouse (Tetrao tetrix), this bird leaps and twists in the air, flashing white feathers and a fantastic tail. As a result, they provide ample interest for behavioural ecologists.

The lek is a paradigm of behavioural ecology and evolution. Males must compete for mating opportunities with females and this usually involves flashy displays. How does this all come about? Firstly, females already invest a lot of energy in their eggs which means they are the limiting factor on reproductive output. Females could just mate randomly with males but they (or their offspring) stand to gain from choosing which males to mate with. Males could provide direct benefits to a female (protection, territory full of resources) or indirect benefits to her offspring by making them fitter (more likely to survive) or sexier (more likely to reproduce).

On what does a female base her choice? Males can prove their fitness in battles of aggression as in rutting deer. Such conflicts are rare in birds, however, with displays being more aesthetic. Investing time and energy into strutting around can only be afforded by a healthy individual. Energy investment is a trade-off and only the fittest individuals can sustain themselves and perform for the ladies. Ornaments are also a costly adaptation, inhibiting movement and attracting predators. By definition, a male who survives to have glossy bright plumage is a survivor which bodes well for his offspring. 

Finally, and especially relevant to the game birds, is immune health. The ability to create large and beautiful ornaments is hampered by disease so only the males with the best immune systems can manage it. The blazing red skin patches of grouse and pheasants is indicative of the parasite load as only males free from infection can metabolise the carotenoids needed to make such colouration. A good immune system is hereditary. But what about all those monogamous birds? They will come later.

Day 6: Grey partridge - Perdix perdix

Partridge in pear tree

Oft called the English partridge, the grey partridge actually has a range that stretches all the way to china. No doubt the national epithet was used to distinguish it from the red-legged ‘French’ partridge (Alectoris rufa) which was introduced to England from France (this species is similarly not confined to its geonym). A partridge takes pride of place in The Twelve Days of Christmas amongst the fruit of the Pyrus tree. 

The song originated in England in the 1780s soon after the introduction of the red-legged partridge but was adapted from similar French carols. Thus the partridge is probably, ironically, French! The pear tree is unique to the English carol however it probably derives from the old French for partridge: pertriz. So should it be a partridge in a partridge?!

The Twelve Days of Christmas celebrates the time of merriment and gift giving between Christmas and the Feast of Epiphany and it teems with birds. If you were lucky enough to receive all of the gifts in the song you would be the proud owner of no less than 184 birds. The second bird on the list is the turtle dove (Streptopelia turtur) which, like the grey partridge, is red listed in the UK. Agricultural intensification has greatly diminished suitable habitat for these agricultural associates causing their populations to crash. Elsewhere on the list we see the hens and geese which would have provided eggs and meat during the cold months whilst calling birds and beautiful swans may have provided some winter joy. Other than that, I’m not sure what these species have in common or why they make the list! 

Day 7: African blue quail - Excalfactoria adansonii 

Good things, small packages

Weighing as little as 30 g and just 5 inches in length this tiny quail is the smallest of the galliforms. By contrast the aforementioned wild turkey weighs as much as 14 kg, 500 times heavier than this quail. This order, therefore, has one of the largest size ranges of any bird order. Size is obviously very important for any organism and is an important form of niche partitioning. 

Different orders represent the first level of niche partitioning in birds (and other animals). There are wild fowl and water fowl, shore birds and birds of prey. Thus, simply put, the order defines the mode of living. Within that, a large part of niche partitioning is based on size. Take raptors as an example, once predatory adaptations evolved, some groups specialised in small prey, some in large prey and the size of their prey defined their own size. Within the Galliformes, size ranges from turkeys to pheasants to partridges to quail, each group occupying relatively discrete size ranges. An ecosystem can only support species which are sufficiently different from each other so rather than have an ecosystem full of quail species, there tend only to be one or two representatives of each group. When we are measuring birds we certainly notice this. We might have a genus with a species in each Asian country which rarely overlap. Then moving to the next genus we start to go over the same countries again. Thus, every island in Indonesia appears to have a magapode, a pheasant and a partridge. Size is only one way that niche space can be partitioned as we will discover later.

Day 8: Golden pheasant - Chrysolophus pictus

King of the pheasants

The golden pheasant was the last galliform that I measured and what a way to finish, in a crescendo of colour across the pheasant species. The birds stand out as an especially colourful bunch in comparison to the more muted colours of the mammals. As in mammals, plainer colours are produced by pigments, particularly melanins with pheomelanins producing the browns and eumelanins producing the greys and blacks. Carotenoids create the fiery colours found in the combs and wattles of the galliforms. 

The truly dazzling feather colours are not produced by pigments but are structural features of the feathers which determine how light is refracted. The iridescent blues and greens are a product of diffraction gratings, regular, parallel lines scored in the nano-structure of the feather. Changes in the angle of the observer cause the colour to shift slightly. Structural colouration can be used in concert with pigmentation to mix and merge colours. It seems that the hairs of mammals are not able to support such adaptation or else highly colourful males would surely have evolved. I wish I understood the physics more! 

To maintain these feathers and to avoid the damage accrued over time, feathers are moulted and replaced. This usually happens after the breeding season when birds are at their most disheveled and it causes them to become more reclusive as they get themselves back in order.

Week 1: Tinamous to Turkeys

Day 1: Yellow-legged tinamou - Crypturellus noctivagus

The First of Many

The very first skin I measured was this nondescript tinamou from the shrubby woodland of eastern Brazil. Despite not being the most exciting birds, tinamous are one of the oldest orders of birds in the world. With the ostriches, rheas, emu, cassowaries and kiwis they form the Palaeognathae (‘old jaw’) which arose in the early Cretaceous (120mya). The palaeognaths are the most basal group of modern birds (Neornithes) which means they are in many ways the most ‘primitive’ lineage. However one must be careful when examining basal groups not to confuse ancestral characteristics (plesiomorphy) with more recently derived characteristics (apomorphy). This will be explained more with the ratites.

The Neornithes (‘new birds’) evolved in the early cretaceous from the small group of birds that had recently begun to flourish. At this stage in their early evolution, different bird groups are classified based on anatomical differences and these can seem small and insignificant. However, whilst there may have been multiple species and groups hopping around the feet of dinosaurs, only one went on to be the ancestor of all modern birds.

Tinamous (as well as a few other basal lineages) exhibit a degree of sexual role reversal where males will incubate the eggs and then rear the chicks of any female that chooses to lay within his territory. Males are simultaneously polygynous as they care for multiple broods from multiple mothers whilst females are sequentially polyandrous, moving from male to male, leaving a clutch of egg where she wanders.

Day 2: Great spotted kiwi - Apteryx haastii

Taxonomic Curio

Kiwis are just weird. This was certainly highlighted from measuring their specimens. The wings are virtually non-existent with the feathers reduced to long down that resembles fur. This condition matches that of many island bird species (rails, crakes, dodos) which, in the absence of terrestrial predators, have forsaken flight for a permanently grounded existence. Flight is energetically costly as is the maintenance of flight feathers so these structures become obsolete in such a relaxed world. This, of course, has deadly consequences when man introduces predators to island havens whether intentionally or not. 

The second feature that became apparent when measuring kiwis was the location of the nostril at the tip of the bill which allows them to detect their invertebrate prey in the soil with their keen sense of smell. Add to this their whisker-like vibrissae and these skulking, furry brown creatures resemble other terrestrial insectivores from around the world including hedgehogs, tenrecs and echidnas. This demonstrates the adaptation of a bird into a normally mammalian niche in a country where mammals (except bats) are naturally absent.

The great spotted kiwi is one of five kiwi species which have their own order: the Apterygiformes (‘without wing’). This particular species which lives on the South Island of New Zealand is the largest of the group. It was identified as a separate species by Julius von Haast, a German geologist and museum founder for which the species is named. Haast also lends his name to the Haast’s eagle, the largest known eagle ever. Weighing up to 15 kg and with a wingspan up to 3 m this huge bird may have terrorised moas and maoris alike before Europeans came to the land.

Day 3: Orange-footed scrubfowl – Megapodius reinwardt

King of the Hill

The orange-footed scrubfowl is a charismatic little bird from south-east Indonesia, New Guinea and north Australia and this was the second time that I had encountered it. I first observed them shuffling through the leaves in Cairns Botanical Gardens, just before I started my MSc project. It was using its large feet to scrape through the leaf litter in search of invertebrates. Thereafter it became a regular in the rainforest bird community, its crest bobbing through the undergrowth and its raucous dawn call waking me up earlier than strictly necessary.

Scrubfowl are a member of the Megapodidae (‘large foot’) which inhabit the forests of SE Asia and Australasia. This group have the peculiar habit of building mounds of vegetation or sand. The mounds act as large incubators using the heat from the decaying vegetation (alternatively solar or geothermal) to warm their eggs. It was surprising to see these tumuli amongst the trees, much bigger than the birds themselves.

  

The megapodes mark my first day working with the Galliformes (‘chicken-shape’), an order which includes turkeys, grouse, partridges and pheasants. Galliformes are partnered with the Anseriformes (ducks, swans and geese) in the clade Galloanserae. The Galloanserae are the first offshoot of the huge group of birds called the Neognathae (‘new jaw’). From now on, all species listed will be neognaths (except when Nico and I get around to measuring the large ratites which are housed separately).

Day 4: Wild turkey – Meleagris gallopavo

40 days until Christmas!

One species that everyone will instantly recognise is the turkey although people are probably more accustomed to seeing it stuffed and served up on a platter than displaying in the woodlands of North America (or in a museum collection for that matter). The nominate subspecies M. g. gallopavo was domesticated in Mesoamerica at least 2,000 years ago where it was associated with the Aztec trickster god Tetzcatlipoca. 

Turkeys were brought to Europe by the Spanish in the 16^th century along with a whole swathe of other resources (imagine Christmas without roast potatoes as well!). Introduced to the English palate by the navigator William Strickland, the turkey soon became the poultry of the rich until the late 19^th Century. Indeed, it was a sign of his recently reformed generosity when Ebenezer Scrooge instructed Bob Cratchit to purchase a Turkey on Christmas Day rather than a goose. 

Nowadays turkey is obviously accessible to everyone and Bernard Matthews currently produces nearly seven million birds each year! Turkey Twizzlers became a matter of contention when Jamie Oliver used them to highlight the unhealthiness of processed foods in schools. It is a pity that such mighty birds should be reduced to so little!