Wildlife – Don't hold your breath

Canada goose + Birds of the Week Invitation CLXXIV

Canada geese (Branta canadensis) are native to north America. Migrating birds were once spotted rarely in Iceland and the extreme west of Ireland, as well as in eastern Siberia. This large goose is unmistakable due to its black head and neck with a white “chin strap”. As in many long-lived birds, the pairs stay together over many breeding seasons. Chicks remain with the parents for a full year, and form a family group which migrates together, until the young find mates in their second spring. I first saw a flock almost thirty years ago in Long Island, USA, but I don’t seem to have a photo from that encounter. There are several subspecies, which differ from each other both genetically and in morphology.

They were introduced into France and UK in the 17th century CE, and soon established feral breeding colonies, which expanded into the rest of Europe by the early 20th century. I saw a breeding pair in the small village of Kirchlengern in northern Germany. The photo here shows one of the pair. They are considered to be pests in Europe, because they drive away native species and overgraze on aquatic grass and sedge.

This is an invitation to share your post about birds, their photos, or their behaviour. If you post about birds this week (starting today and up to next Monday), you could leave a link in the comments, or a pingback, for others to follow. You don’t have to have a recent photo, nor do you have to post a photo of the same bird as mine. Do use the tag “Bird of the Week” to help others find your post, and remember to visit other people’s posts. For more information see the main landing page for this invitation.

Birds of the Week CLXXIII

Egyptian goose + Birds of the Week Invitation CLXXIII

Spotting a gaggle of Egyptian geese (Alopochen aegyptiaca) in a park in Darmstadt surprised me. I was sure of the identification: the brown mask is a giveaway, and is supported by the colour of the beak, the pink legs, and a brown patch on the breast. I’d previously only seen them in Kenya, and I’d put them down as a species from sub-Saharan Africa. I found later that my memory was not wrong. It was introduced into UK in the 17th century, but in the Netherlands only in the 1980s, and expanded from there into the rest of Europe. The expansion had just begun when I lived in Germany, so I’d missed them earlier. Breeding populations are now also found in the US. The featured photo is evidence of it breeding in Germany. The two below show it in its native habitats in Africa.

The chicks made me curious about its breeding and mating behaviour. Like most birds, there is pair bonding. Since the young develop in eggs, nests have to be defended, and brooding adults have to be nourished. This is the evolutionary pressure behind pair bonding in birds, at least for a season. But pairs of Egyptian geese bond over several seasons, often for life. In the past behaviour such as this was taken to be a moral example. But behaviour is driven by biology and its imperatives. So it is interesting to try to figure out driver behind such long-term pair-bonding.

The question has exercised several generations of evolutionary biologists. Field studies with several species show that long-term pair bonding improves fertility in long-lived species of birds. The reasons are not yet totally clear. In some species birds begin to play mating games for a year or two before they are mature enough to breed, and it is believed that long-term pairs are formed in this process. If so, it would seem to require effort and time to form new pairs, so reducing the time in each spring during which successful breeding can occur. With our very detailed knowledge of the complexity of long-term pair-bonding in one species, we can imagine that there is much more to this story. There is also interesting speculation about how long-term pair-bonding may lead to the evolution of cooperation.

Birds of the Week CLXXII

Eurasian Coot + Birds of the Week Invitation CLXXII

On my first ever trip specially for bird-watching I saw an enormous number of small water birds which were very distinctive. They were completely black (head and shoulders glossy but sooty body) and had a standout white bill and frontal shield. These were Eurasian coots (Fulica atra, also called common coots). They were unforgettable, especially since, for years, I would spot flocks every time I passed near water. They seem to be less common now, but I’ve not really kept count and cannot dispute the general agreement that it is of least concern for conservation efforts. But I’d never seen the chicks before: in India the breeding season is during the monsoon, and I do almost no bird-watching at that time.

In mid-May, when I was out for a walk with a friend, next to a fast-flowing stream in Germany, I saw the chicks that you can see in the featured photo. They were beginning to lose their down and the emerging plumage was very dark. They were not the young of ducks or geese. I don’t know most of the birds of Europe, but I had a feeling that these could be the chicks of Eurasian coots. Nothing else I knew was so dark. Soon enough, a parent came paddling by, and my guess was verified. Later I read that the young will retain the white on their neck and face for some time. The beak will change colour, and the frontal shield will develop at about the time the plumage turns darker.

Eurasian coot, Fulica atra, adult with nest

The chicks were too young to have wandered too far from their nest. I looked around, and on the riverbank nearby I saw another parent near a nest. A nest very close to water, emerging from vegetation, and resting on it, is said to be common. Sometimes, though, they have been seen floating on water. In no sense can this be called a lifer, but I was very excited to see the hatchlings of coots, and a nest, for the first time. For me, watching birds is not only about keeping a score of the species that I have seen. It is also about watching the behaviour of birds. Nesting and rearing of the young, hunting and feeding, mating rituals, are all interesting things to observe.

Birds of the Week CLXXI

Tufted Duck + Birds of the Week Invitation CLXXI

Boldly patterned, small, golden eyed, and commonly found. That’s a tufted duck (Aythya fuligula) for you. I’ve found it swimming in the waters of a small pond in Rajasthan, a reservoir in the plains of Uttarakhand, in the freezing water around Gamla Stan in Stockholm, and, most recently, on the murky waters of the Elbe near Hamburg’s harbour. I’ve generally seen large flocks, but this time, in spring, I saw only a pair. The tuft of the male is pretty noticeable, as you can see in the featured photo. The black back persists in the tuftless brown female. As always, the sexual dimorphism indicates different roles in nesting. The females do the incubation and rear the chicks alone for four to six weeks by the female alone. The unfledged chicks are then left to fend for themselves.

Tufted duck, Aythya fuligula, Hamburg Elbe

The strangely lopsided and careless pattern of breeding also leaves space for brood parasitism, by other females of the same species, or of another. Typically a clutch has six to eight eggs, but it is not unusual to find nests with a dozen or more eggs. I would guess that the frequency with which these large clutches are found indicate significant chances of brood parasitism. It is a wonder that with this style of nesting the species is far from endangered today. It is not only widespread across most of Eurasia, but also common, with a world population of more than a million. This should have something to do with its adaptability in choosing habitats. It has been found at heights of 2400 meters in the Alps, brackish as well as fresh water, streams, lakes, and even the sea.

Birds of the Week CLXX

Barking mad

Once I would see a barking deer in India and tell you that I’d seen a specimen of Muntiacus muntjak. No longer. This name turned out to hide a couple of different species. I saw this one in the plains at the foot of the Himalayas, close to the Nepal-India border. So I should provisionally call this a Northern red muntjac (Muntiacus vaginalis), whose range is said to cover most of northern India. After seeing this I looked carefully at the ranges of the 14 species of barking deer (genus Muntiacus). All fourteen are natives of southern China, and south and south-east Asia. You can find four more in India, three being crowded into the east and north-east of the country.

I found it intriguing that so many species of muntjacs can be found in very small, ranges adjacent to each other. Why don’t they interbreed? I was glad to find that through most of my life a section of evolutionary biologists have asked precisely this question. It turns out that barking deer have speciated by very quick changes in the number of chromosomes. It was reported as early as 1970 that M. muntjak and malabaricus have 3 pairs of chromosomes (for females; and an extra chromosome for males!), whereas the Reeve’s muntjac (M. reevesii) has 23 pairs. This change makes it impossible for these two closely related species to interbreed. Simply counting chromosome numbers allowed people to mark out other species. An extensive study is yet to be done for red muntjacs. So it is possible that there might be several other species hiding in plain sight. Finding them (or ruling this out) will require a little bit of funding for field and lab studies, perhaps at the level of the cost of a single Tomahawk missile spread over ten years.

But to get back to the Northern red muntjac, it turns out that after the change in the chromosome number, their genes have evolved furiously. It turns out that the whole genus Muntiacus is extreme in the rate of change in chromosome numbers. In fact, it was found that in Black muntjacs (M. crinifrons) the sex chromosomes X and Y have fused with other chromosomes. However, this method of evolution has been seen across the deer family (Cervidae). It has been inferred that the primitive representative of Cervidae had 35 pairs of chromosomes and different kinds of fusion between them gave rise to different phyla.

Little cormorant + Birds of the Week Invitation CLXX

Never before have I looked down at a Little cormorant (Microcarbo niger) swimming. Standing on a bridge above this stream in Pilibhit Tiger Reserve, I could see how it uses it normally rigid tail as a rudder. The stream was shallow, but must have had small fish. It dived a few times, but came up without anything in its mouth. Cormorants feed by throwing its catch in the air and swallowing it head first, so I should have seen it if it had caught something. They do eat frogs and tadpoles, but in this flowing water I didn’t think there were tadpoles. I wonder what fraction of its dives result in a catch (I got AI generated answers, but since they did not hit on a field study, I can’t trust the result). When you have a new perspective on a bird, new questions come to your mind.

Birds of the Week CLXIX

Indian Grey hornbill + Birds of the Week Invitation CLXIX

Light of this kind is not easy to come by, so I didn’t hesitate to click a photo of this male Indian grey hornbill (Ocyceros birostris) sitting on top of a tree. I’ve written about them many times before so let me just remark on one behaviour that I’ve seen. For years we saw a pair nesting in a tree hole visible from our balcony. Now and then I would see two birds locking bills as if wrestling. When I saw this behaviour, it would usually be the chicks which were doing this. I put it down to play. But once I’d seen the adult couple bill-wrestling. I recently came across a paper which claimed it was a courtship ritual. Pairs of these birds apparently bond for life, so this behaviour could be more plastic than courtship. I wonder.

Birds of the Week CLXVIII

A Jezebel

Hong Kong is too urban to find any wildlife in the short stay we had there, I thought. So I was quite surprised to see a Red-base Jezebel (Delias pasithoe) quietly waiting for me to take a photo of it on a road in the morning. I can recognize a Jezebel when I see one on the road (I can see some eye rolling there, but never mind) so it didn’t take me long to figure out its full identity. A lifer, although butterfly watchers don’t use that term. They are usual in montane forests at low heights, below about 1500 meters. Strange that I never saw one in Nepal or Sikkim, where they are common, and ran into one here.

Chestnut-headed Bee-eater + Birds of the Week Invitation CLXVIII

Solitary or gregarious? When I posted about Chestnut-headed bee-eaters (Merops leschenaulti) before, I’d written that they are gregarious. But after seeing some again in Pilibhit Tiger Reserve I wondered. I could see one most of the time, and a pair now and then. I went back and looked at the photos that I have, and found that I’ve only ever photographed solitary birds. I’ve seen many green bee-eaters all huddled up together in mornings, but never a crowd of these. Apparently they are known to nest either individually or in small colonies. So I’ll keep the answer as a provisional “mostly solitary”, and keep open other options for now.

Birds of the Week CLXVII

Indian Jackal and a deep dive into the notion of species

Quick shot and dismissal. That was how I treated this jackal in the field when I passed it in Pilibhit Tiger Reserve (photo above). Folktales and stories about the trickster, the canny jackal, are common across India. Later, when I looked at the photo again and decided to refresh my memory about jackals by reading the literature, I realized that they are worth more of our time and effort. So much attention is paid to pet dogs in life and media that we forget that the study of wild dogs, genus Canis is one of the most neglected fields in the world today. Was this a Himalayan golden jackal or an Indian golden jackal? Is there a difference? Look at the photos here to see the changes in coat colour from north to south. Both are currently called Canis aureus indicus, but there are too few studies to figure out whether that is their true taxonomic status. Are they really identical? Are they subspecies of a widespread species called Canis aureus? Or is C. aureus a species complex which contains populations waiting for recognition as species?

See this for the standard definition of a species.

Why does it matter? A recent paper on the taxonomy of grey wolves gave me a clear answer, “The concept of a species is important, as legislation, conservation and the non-specialist science community rely on these taxonomic divisions and need species.” In spite of the human need to put a boundary on the slow constant flux of genes, there are always ambiguities. For example, there is even some dispute about the distinction between grey wolves (Canis lupus) and golden jackals (Canis aureus). Although there is strong evidence for the separation of these two species from about 1 million years ago, there is also evidence for more recent gene flow between them, possibly leading to hybrids which are now recognized as a third species. All this seems to be contradictory to our notions of species. Many experts now agree that the notion of a species is complex, and say that it is a “simplified representation of natural variation” and what is needed is to choose “an approach to delineate units for conservation recovery planning that recognizes the dynamic nature of natural systems.”

Jackal in Pench National Park — Indian golden jackal in Pench NP

African wolves (Canis lupaster) have already been split away from Golden jackals (Canis aureus) a decade ago. Tibetan and Indian wolves have long been considered as subspecies of grey wolves (Canis lupus), but this status is currently under dispute. Extensive work on wolves has currently resulted in the recommendation: “The Himalayan/Tibetan and Indian wolf lineages appear to have diverged earlier and are distinct from all other grey wolves (C. lupus) based on mitochondrial and nuclear genome data. However, until genome-wide data from multiple individuals across the range clarify relationships with other taxa, we suggest referring to the Himalayan/Tibetan wolf lineage as Canis lupus chanco. We support the currently accepted nomenclature for the Indian wolf Canis lupus pallipes for the wolf populations found on the Indian subcontinent and possibly also in south-western Asia (exact geographical boundary pending).”

The current uncertain status of family Canidae has resulted in the development of a notion of evolutionary significant unit (ESU). As taxonomists work their slow way towards the delimitations of species, they generate data which can be used by conservationists who try to preserve natural variation captured in ESUs. In this process, the Indian/Himalayan jackal is an ESU. Are there actually two ESUs here, the Himalayan and the plains populations? Further studies are pending.