Winter birds
Look and listen in lock-down
Contrary to most of what you read and hear about birds in winter, the season’s hardships are — with the exception of a prolonged big freeze — easier to bear than the stress of the breeding season. In winter, birds look to their own needs. Many species form flocks, meaning multiple eyes are peeled for predators and finding food. Cooperation means more survive.
It does not take much to fill a songbird’s stomach. If all goes well, a few feeding sessions — concentrated in the morning, when the bird is hungry — will suffice. Winter afternoons are quiet affairs. After lunch, Starlings idle on telephone wires like rows of sheet music, burbling before bedtime. Morning rush-hours at feeding stations have no evening equivalent. As early as 3pm, a male Great Tit disappears for the night inside a nestbox — no bedding, just dry walls. Its only contact with terra firma is through the feet, which have no blood circulation. It balloons out underlying plumage and cocoons its vital organs in a duvet of down.
Winter days may be short but, after Christmas, they lengthen by around two minutes per day — or about fifteen minutes a week. Increasing day length has a massive influence on the natural world. We may go to bed in the dark and not see daylight when we wake. But the subtle change in ‘photo-period’ triggers breeding preparations in birds. The duration of daylight is a reliable switch — more dependable than weather or other environmental cues. Longer days stimulate birds sex organs to regrow. Courtship arias follow. But not, at first, for all. If a winter territory is not also a breeding territory, there is no point singing for a mate there.
The exception to this rule is a handful of resident species. In Ireland, that means Robins, Wrens, Dunnocks, members of the tit family — and some thrushes. You might think the list of early singers would include Blackbird and Chaffinch. Both are abundant breeding birds. However, many of those we see in winter come from overseas. It seems as though ‘our lot’ save their energy for warmer conditions in early spring — when the visitors leave. Because winter airwaves are less crowded, the few songs stand out. Here, to lighten lock-down, is a cameo of the chief songsters in January and February. Remember, all birds have a wide vocabulary — song is just a part of a more complex language.
Although Blackbirds do not sing earnestly until March, they provide another insight into how birds live — by demonstrating how plumage is upgraded. Red apples (or dry porridge flakes) brings Blackbirds within easy viewing distance. Close-up, you can discover how they change their feathers and morph from a speckled youngster to what we see in winter — jet-black males or peat-coloured females. You might be surprised to find that, in fact, few are alike.
WREN
Although, like all birds, Wrens need to renew their plumage and have set moulting times — such as, for adults, at the end of the breeding season — they replace like with like, so they always look the same throughout the year. Male Wrens seem to invest in long-term occupancy of a territory, only moving away temporarily during adverse conditions. Females, on the other hand, appear to be more mobile and, since males are inclined to be single owner-occupiers, females and young account for the majority of Wrens found in reed-beds, a wintertime haunt not deemed suitable breeding habitat by territorial males. According to Edward Armstrong, an Ulster cleric and author of The Wren, established males do not sing in earnest until early spring. Nonetheless, song is an everyday winter occurrence — mainly as a reveille denoting presence and proprietorial rights, rather than expressing courtship intent.
Ringing data confirm a lack of migration by British and Irish Wrens (many north European populations are, however, migratory) but some show wanderlust — such as dispersing juveniles. The BTO Migration Atlas documents five movements of over 20 km by Wrens in Ireland. Three of the five recoveries involved birds trapped at Copeland Bird Observatory and subsequently found elsewhere in Co. Down or Co. Antrim. The stand-out recovery features a bird ringed on the Yorkshire coast and recovered in Co. Monaghan. Having crossed the Irish Sea, this individual may even have originated much further afield, possibly Scandinavia. In the past, Irish lighthouse keepers regularly reported Wrens in autumn and early winter — typically discovered dead after becoming dazzled and hitting the lighthouse on rainy or misty nights. Given that many reports came from lonely rocks where no Wrens bred, such casualties were inbound to Ireland from across various seas.
You can listen here to Wren song: https://www.xeno-canto.org/191029
DUNNOCK
Common but anonymous. Those two adjectives sum up Dunnock and help explain why many casual observers are unsure of the bird’s identity when they see their first. An unobtrusive nature is complemented by demeanour. Dunnocks are edgy; they shuffle along with a crouching gait and have a distinctive habit of flicking one wing, like a manic driver indicating to overtake.The sexes are similar and it is difficult to tell ages apart. Just for the record, the bird in the image is a male (because it is singing).
Male Dunnocks are one of the year’s earliest singers. When they start in January, they are hoping to interest a female. Song indicates ownership of potential breeding territory. The problem is, every male worth his salt is at the same game. Contestants know each other and, for a variety of surprisingly complicated reasons, copy bits of each others songs.
To the ears of a female, a pretty tune only takes you so far. She wants more than a good crooner — she needs territory stocked with sufficient food to raise a family. Hers is the whip hand. What began as ‘one male, one territory’ is subsumed into an overarching female empire in which a matriarch maintains multiple partners. Because all involved in the shenanigans stick around, there are male winners and male losers. Relations are fraught but, eventually, young Dunnocks of various paternal suites are raised.
Against this background, it becomes easier to understand the frenetic nature of song, particularly in March when preparations for the new mating season are in full swing. Because of constant eaves-dropping, when one Dunnock sings, a neighbour answers. Next time you hear one start up, there’s a good chance that another will chip in — invariably in the gaps between song bursts.
In keeping with the bird’s nondescript appearance (although I find Dunnock plumage exquisite), the song also comes across as less than overwhelming:
https://www.xeno-canto.org/459842
Not loud, not prolonged and not easy to cement into the brain using a ‘handle’ — meaning, a likeness to something that sticks. I used to think that a useful tip was to point out that, of all common bird songs, Dunnock’s tune could be identified through its lack of a distinctive pattern. But that’s like throwing in the towel. Listening more, I can (in my head) liken the sound to the indecipherable jumble of a song being rewound on a music cassette or CD.
ROBIN
‘Robins are familiar birds throughout most of Britain and Ireland. Ironically, given how much they have taught us about how birds navigate during migration, there are surprising gaps in our knowledge of their movements in Britain and Ireland.’
The words, from the British Trust for Ornithology’s Migration Atlas (2002) are David Harper’s — qualified to comment because he studied the species intensively for a doctorate at Cambridge University, which informs the species account in The Birds of the Western Palaearctic (1988). Harper’s study was preceded by research carried out by J.P.Burkitt in Co. Fermanagh, the first person to conduct a ringing study on wild birds using metal rings. Burkitt’s research ran from October 1922 to March 1926 [1]. Despite being widely misquoted, Burkitt did not ‘colour-ring’ his Robins: ‘I gave up my first idea of coloured rings as quite too difficult of detection.’ Instead, he used aluminium bands, that he rendered black or white. Concerned that he might discomfort the birds, he restricted configurations to no more than four rings per bird, which, over time, almost took him ‘to the limit of variations.’ Burkitt was so thorough in his approach and observations that Harper was able to make direct comparisons — and corroborate most of Burkitt’s findings.
Robins occur widely across Europe. Northern populations, such as in Sweden, are migratory: ‘the great majority migrate … towards southwest Europe and North Africa. During September, they are moving south. Most have left Sweden after October, but some stay on if the autumn is a mild one.’ [2] Populations in southern Europe are, however, resident. Falling between the two poles of migration, Robins in Ireland and Britain are partly migratory. Given the travels of northern populations, it is no surprise to discover that some occur this far west. In the late nineteenth century, Richard Barrington collated twenty years of reports from lighthouse keepers around the Irish coast (consisting mainly of birds that died when they struck the light) and summarised Robin’s migratory status thus: ‘the period of maximum spring migration includes the first ten days of April and runs from about 12th March to 12th April. The main period in autumn covers the last ten days of September, and seems to extend from 20th September to 20th October.’ [3]
Where are these Robins from? Although ringing recoveries are something of a lottery, it is remarkable that of over 8,000 recoveries of Robins ringed in Britain and Ireland, just one crossed the Irish Sea to Ireland (a Robin ringed on the Isle of Man). Maybe the majority of Robins recorded at migration seasons by lighthouse keepers came from no further away than the Irish mainland? Or are Scandinavian migrants commoner than we think?
By way of confirmation that an unknown number of Scandinavian Robins continue to pass through Ireland, two trapped at Copeland Bird Observatory, Co. Down, generated recoveries in Norway during the breeding season and Spain in January. The Spanish bird had been ringed at Copeland Bird Observatory the previous March when it was probably en route back to Scandinavia from a previous winter spent in Spain.
Accepting that the bulk of our population is resident, questions arise over the changing distribution of the species throughout the year. Burkitt summarised his results as follows. Adult males normally retain the whole or part of a breeding territory throughout the year, and from year to year. Females wander. Some may spend the winter in or near the place where they bred. However, once the breeding season is over — after which all adults moult in late summer — there is no bond between the pair. Each is independent and occupies its own territory for the winter. Therefore, for females and young, the ‘homeplace’ is not available — because the adult male will remain there. In Burkitt’s study area he was struck by the wholesale evacuation of all his marked females after the breeding season. He went as far as to say, ‘they left en masse. Most are not seen again. A very few reappear, occupying sites in mid-autumn.’ Youngsters also wander — in random directions. They too need a territory for the coming winter. Although some young and some adult females succeed in establishing a winter ‘residence’, Burkitt felt that a proportion fail to secure a dominion and are probably nomadic until the New Year — when they attempt to find a mate, a quest that tends to draw them back to where they originated. Hence, even though post-breeding dispersal by females and youngsters is on a grand scale, the distances involved may be short: ‘of Robins present in Britain and Ireland during the breeding season and located elsewhere at other times of the year, only 10% (of 2,454) had moved more than 20km.’ (BTO Migration Atlas)
Mystery still remains because, based on results of several colour-ringing studies, winter sightings of Robins in all habitats in Britain and Ireland are heavily biased towards males with, in spring time, a return of females. Burkitt noted precisely the same: ‘of my nine winter residents which did not leave, all were males except one. Of the ten immigrants [newcomers that arrived in the New Year and paired with a winter resident] eight proved to be females. [Other, unmarked birds that passed through in late winter and early spring] were presumably females, as practically all of them were in [temporary] peaceable companionship with my resident males.’ Where were the females during winter?
If, like Blackbirds, Robins differed in appearance, males, females and even the sex of youngsters could be determined up to the age of their first birthday (see Blackbird account below). That way, the location of female Robins would be more straightforward. Although it is possible to tell the age (not the sex) of a Robin in winter, it is far from easy.
Given more than a century of ringing, with almost 700,000 Robins ringed and nearly 9,000 recoveries, data suggests that the vast majority of British and Irish Robins are unadventurous throughout their brief lives — whether dispersing as juveniles, females vacating territory at the end of a breeding partnership, or roaming a significant distance in search of winter quarters or new breeding areas. Between 1967 and 2002 (and possibly since) no Robin ringed as a nestling in Britain or Ireland has been recovered abroad — even though it is strongly suspected that some from these islands do winter overseas. Between 1913 and 1963, eight English Robins were found on the Continent in winter (six in France and one each in Holland and Spain).
It is not unusual to see Robins in proximity in winter, generally where there is plenty of food — or if a few birds learn that someone provides handouts in one spot on a regular basis. The reason for the assembly and the communal ‘burying the hatchet’ is because each has ventured from its territory to exploit the boon. The territory holder on whose ‘property’ the easy pickings are available will still attempt to drive away trespassers, although this may become a thankless task.
Listen here to a Robin singing at night: https://www.xeno-canto.org/211318
Song is an important mechanism to advertise possession of a winter territory. Given that females — as well as males — defend a territory in winter, they have just as much reason to sing. And they do. Thanks to Burkitt’s use of rings, he was the first to discover that females sang: ‘I started my study with the assumption that all singing Robins were cocks, and was therefore much astonished, on April 7th, to see this bird [no.11 in his numbered Robins] being fed by another, thus suggesting that no.11 was a female, and such it turned out to be.’
It is important to draw a distinction between singing to attract a mate and singing to proclaim ownership of a winter feeding territory. Song from female Robins is used exclusively for the latter — only males sing to attract a mate. Consequently the great outpouring of song in January is overwhelmingly from males advertising for a mate. New partnerships can be forged as early as January, although the courtship period runs until April. If winter weather is mild, early nesting is not unusual: ‘I have seen one building in March, and have known of young hatched on 7th April. Mr T.B. Gibson records young Robins fully fledged on 7th February, near Ferns, Co. Wexford.’ [4]
Simply because female Robins are known to use song as a means to assert ownership of a winter feeding territory does not mean that they are especially vocal. Rather, any bursts of female song seem to be on a ‘needs must’ basis. Burkitt, having established that females sing, quantified the singing rate: ‘probably every female sings an occasional bar during her sole occupation of a territory; but the total of such song is almost negligible. Any appreciable song heard frequently from a Robin seems to denote a male.’ As he neared the end of his study, Burkitt confirmed this supposition: ‘with regard to female song, each of the three marked females that took up sites around me this autumn were heard to sing, but the total for the whole autumn was only a few feeble bars, and these were generally made on occasions of hostility.’
What of the song itself? Dip into reference books, such as The Birds of the Western Palaearctic, and you come across statements claiming that, compared to female Robin song, male Robin song is ‘of greater duration, diversity and repetition rate’ (BWP, vol.5, p.610). An alternative explanation is the motivation of the singer. When you begin to understand that a female is singing to keep intruders away, whereas a male could be singing his socks off to impress a potential breeding partner — of course there is a difference. As for ‘repetition’, one of the nicest qualities of Robin song is that no two phrases sound the same.
‘About the fourth week in January the males in singing voice begin to perch higher, even to the tops of trees … [if they have failed to attract a mate] they nearly always sing well up and exposed, but mated males will not necessarily do so, and more usually do not. From early March the mated birds give distinctly less song than those without mates.’ J.P.Burkitt.
About the only thing upon which Burkitt did not elaborate is Robin’s penchant for singing in the dark. Winter nights are enlivened by the birds’ evocative singing, which proceeds by short compositions; each sounding like a melancholic opening to a verse that dies just after is has begun. Although broadcasts can be heard after dusk right up to Christmas, they are erratic. Pre-dawn darkness is far more dependable. It is, of course, in the bird’s interest to sing more at the end of the night — because each lets its neighbours know that it is still around. At the end of still winter nights all territory-holders participate in a linear chorus of sound. There is no ‘wall of sound’ because the volume carries a relatively short distance — but far enough to reach the ears of a nearest neighbour.
Walking around gardens in suburbia in snowy darkness in late January, it is obvious that a kind of etiquette applies to all singers — which, presumably, are males hoping to attract breeding partners. The gaps in one bird’s song offer space for its neighbour to respond. Singers do not overlap. Choice of song posts is ‘high vegetation, near a street lamp’. Telephone wires or rooftops are avoided, probably because they are too exposed if danger threatens. Preference for a well-lit song perch is less easy to explain but nearby dark woods had no singers, compared to the string of pearls distribution along lamp-lit, well timbered gardens. By Robin standards, singing was intense throughout the final two hours of the night. It seemed as though every male was involved in setting out his stall. By daybreak, the intensity declined. Those that carried on did so at a more leisurely pace, with longer gaps between bouts of singing and minimal responses from neighbours. Given that daylight had arrived, finding real food rather than making music — the food of love — was more important.
January pre-dawn singing: https://www.xeno-canto.org/618557
[1] Burkitt, J.P. 1924. A study of the Robin by means of marked birds. British Birds 17:294–303. Four subsequent papers with the same name (although numbered sequentially) were published in British Birds in 1925, 1926 and 1927. These references are: 18:97–103 and 250–257; 19:120–124; 20:91–101.
[2] Jonsson, L. 2015. Winter Birds p.121. Bloomsbury.
[3] Barrington, R.M. 1900. Migration of Birds at Irish Light Stations.
[4] Ussher, R.J. & Warren, R. 1900. The Birds of Ireland p.13.Gurney & Jackson, London.
SONG THRUSH
Although Song Thrushes sing occasionally before Christmas, broadcasts then are little more than practice sessions by young males or idling by adult males, prompted to sing by calm, mild conditions and a full belly at evening time. Irrespective or age or motivation, all in the population sense the need to do a sound-check because, in January, they start to sing in earnest. Apparently, younger males go first. Their efforts are more in hope than expectation.
‘Song Thrush’ is a bit of a misnomer. ‘Philomelos’, the second part of Turdus philomelos, the scientific name, translates to mean ‘lover of song’. The aria is hardly melodic; its main characteristics are loudness and repetition. The repetition is critical for identification. The only confusion species — Blackbird and Mistle Thrush — do not repeat notes or phrases. A Song Thrush broadcast feels more like narration than song. I have added a link to a singer on Inishbofin where the bird has become common and, for reasons that I do not understand, tolerant of human onlookers when rapt in its rhymes.
Listen here to Song Thrush: https://www.xeno-canto.org/184173
Unless the end of a dark night is wet and windy, the first bars are uttered in before dawn. As daylight lengthens and sunrise comes sooner, the singers also rise early. In truth, they have to — silence invites invasion from interlopers seeking territory or a breeding partner. Although we enjoy the performance, it may be all work and no play for the contestants.
SONG OR MISTLE THRUSH?
Mistle Thrush is noticeably larger than Song Thrush. That last sentence is, however, usually useless. I do not know how many times I have seen the two species in direct proximity — probably never. Mistle Thrush is an extrovert that likes to bounce around in the open, head up and bossy , with a bulging belly. Ironically, compared to the more diminutive Song Thrush, Mistle Thrush is, in proportion, smaller headed. Song Thrush is more stocky — and also shy. Except when singing, they look edgy; stop-start body language expresses a sense of unease. Song Thrushes feed on the ground — the species seldom perches in bushes to pluck berries — and hold themselves in a forwards-leaning crouch. Although famed for cracking open snails on a hard surface, earthworms are probably preferred. For one thing, there is less work in preparing dinner.
Plumage-wise, where do you begin? A spotted underside is the hallmark of a thrush but the spots on the body of a Song Thrush are hardly ‘spot-shaped’. They are tear-shaped and pointed at one end — aligned in ‘organised’ rows facing the head. Looking at the pattern on the flanks, there is a sense of order in Song Thrush that is lacking in Mistle Thrush. Mistle Thrush has ‘random’ spots; at a distance, they look like black hailstones. The spots coalesce into a dark patch on the side of the neck. Other distinctions include, during autumn and winter, a brassy tint to all the under-parts in Mistle Thrush. On Song Thrush, just the chest has a honey-coloured wash. Be aware that, as early as February, Mistle Thrushes can look monochrome — especially across the chest and belly, where the spots are dotted on a whitish background.
Overall, Mistle Thrush is stone-coloured. The folded wings and tracts of wing-coverts are etched like layers of sedimentary rock. Although both Song and Mistle Thrushes have strongly patterned heads, Mistle Thrush is fundamentally grey — ashen-faced. Song Thrush looks brown-capped, noticeably so during feeding activities when the head is held crooked. Facial markings on Song Thrush appear messy, especially below the eye where dark rivulets resemble runny mascara. In flight, Mistle Thrush — by far a stronger flier, usually incorporating deep undulations — reveals white underwings (on Song Thrush, the underwing colour is ‘golden toast’) and its longer tail flashes white corners.
Both Song Thrush and Mistle Thrush occasionally sing on mild winter days. Mistle Thrush has a penchant for singing in heavy overcast or even light rain (justifying its nick-name ‘Stormcock’). Most other birds are silent then.
The spanner in the works is Blackbird. Visually, Blackbird is a no-brainer to identify. But, to the uninitiated, the two sound similar. However, only Mistle Thrush is in full voice between January and March — Blackbirds wait until March before they burst en masse upon the airwaves. Accordingly, any ‘thrush-like’ song in deep winter is most likely to be from a Mistle Thrush (assuming that Song Thrush, thanks to its repetitive phrasing, is excluded). Let’s start with listening to a Mistle Thrush. At the end of the recording you can also hear a distinctive rattle, used by Mistle Thrushes to sound alarm or signal aggressive intent. During winter, Mistle Thrushes defend berry-laden trees and deter intruders with airborne attacks accompanied by loud rattling.
Listen here to song followed by a rattling call: https://www.xeno-canto.org/615216
Mistle Thrush delivers short phrases separated by gaps. The more relaxed the the singer, the longer the gaps. Given that morning song is designed to remind rivals that a territory-holder is present and singing his utmost to impress a mate, his performance is likely to be at a high tempo — so the gaps between phrases are short. Less stressed later in the day, the gaps lengthen. Each phrase may have just two or three syllables — or, less often, up to six. The sound has a ‘solemn sermon’ feel. Phrases have little variation and quickly becomes monotonous. The combination of regularly spaced gaps and similar-sounding song phrases generates a hypnotic effect, compounded by the singer continuing for minutes on end.
Now for Blackbird. This bird is the melody maestro. Unlike Mistle Thrush, its notes are silky and ‘slide’ from one to another. Another hallmark is a habit of raising the end of phrases into a high-pitched ‘Bee-Gees’ crescendo. Unlike Mistle Thrush, each in a series of Blackbird’s phrases do not come across as carbon copies. In other words, Blackbird is never boring. The more you listen and ‘dissect’ what you hear, the more you will discover your own identification handle. Especially in April, daybreak singing by closely-spaced Blackbirds is so concentrated and overlapping that the song dominates the dawn chorus. Mistle Thrushes are far less tolerant of rival singers. Their territories are large and broadcast distances are wide — and often uncontested.
Listen here to Blackbird: https://www.xeno-canto.org/180812
You can click on the link to hear a difference in intensity in song between dawn and dusk. Dawn singing has a more pressing need to advertise continued presence at the end of the night and keep rivals at bay. As the day wears on, the singer becomes more laid back. By evening, he is king of his castle. Sonograms of the two recordings are shown below.
TELLING THE AGE OF BLACKBIRDS IN WINTER
Nesting strategies divide the world’s birds into two camps. Some chicks are born covered in down whereas others, such as Blackbirds, hatch naked but immediately begin to grow feathers. Swaddled by a parent and protected within a nest, the baby cannot leave until it can flutter away under its own steam. The youngster’s first coat of plumage grows rapidly. Mammalian predators will be deprived of easy pickings the sooner it leaves the nest and hides in dense undergrowth. To increase the chances of not being detected, juvenile plumage is dark and somewhat mottled, especially below.
Feathers grown in the nest fall into two categories — broadly speaking, numerous small ‘contour feathers’ covering the body, and a smaller quantity of bigger, rigid feathers designed to fit together exactly to form wings and tail. In common with most species, the wing and tail feathers remain on the young Blackbird until just past its first birthday. Because these feathers are large, they take time to produce — so most recently fledged songbirds become independent with wings and a tail that are still growing. Even upon completion, the juvenile wing and tail differ slightly in shape from those of an adult. First editions of ‘adult’ feathers are slightly narrower, more pointed and shorter.
Juvenile body plumage sprouts quickly but is not hard-wearing. It has a short shelf life. It may look pretty — lacy and delicate with speckles for camouflage — but along the shaft of each feather there are fewer barbs and the tip is loose with no interlocking structure to hold the end together. Furthermore, the quantity of plumage is less than on an adult. Beneath a feathered exterior, parts of the body remain bare. Within weeks most of the ‘economy class’ juvenile plumage is replaced by adult attire. By late autumn, youngsters fledged over the summer have acquired a fresh set of body feathers — but retain the costly-to-produce big feathers that make up the wings and tail.
This last point bears repeating: although an immature Blackbird goes through two different plumages in the course of its first year, it keeps its original wings and tail (plus a few large covert feathers cloaking the wing). Therefore, during autumn and throughout the forthcoming winter, although its appearance is adult-like, there are minor differences from mature adults.
Young male Blackbirds reveal their age thanks to the colour difference between ‘new’ black body plumage — but ‘old’ brown wings. Young females, while they too have two generations of plumage, are far more like an adult female — because all of their plumage, whether young or old, is brown.
A further ageing method is available. While a good view is essential, the feature is definitive and arises through the whim of individuals choosing to moult some of the largest juvenile wing coverts, known as greater coverts, which straddle the flight feathers.
A useful way to grasp the concept is to think of milk teeth in children. At some stage in the process of dispensing with baby teeth and growing adult replacements, a child will have two generations of teeth. And the two ages can be told apart. Likewise, because some of an immature Blackbird’s greater coverts are, like milk teeth, replaced, they differ from adjoining feathers in the same row of feathers. Just like milk teeth, they are smaller and narrower. Because feathers are replaced in sequence, starting from the inner part of the wing and progressing outwards, new adult-like feathers sit closer to the base of the wing. Consequently, when the row of coverts is examined, there will be a contrast — called a moult contrast — and one set of feathers will look different. Why? Because the new adult feathers are better quality and more durable. And, vitally, they are a different colour. In young males, the new feathers are black; in females, a different shade of brown. So it doesn’t take a genius to work out that seeing the difference and telling the age of a young male, is a lot easier than for a female. Practice makes it possible, however.
BLUE TIT, THE POLYGLOT
Along with Great Tit, Blue Tits share a higher level of intelligence than most other birds. Probably as a consequence, they have a wide vocabulary. They seem to like to comment on everything they see — including the arrival of a human in what they regard as their beat. Even the act of refilling a feeder elicits scolding! All is forgiven when, in January, males include in their repertoire a silvery quaver — a ‘trembling tremolo’ — that qualifies as song. As with many sounds in Blue Tit vocabulary, there is some variation. However, the basic pattern consists of a hissing opening note (such as ‘pitz’), whose ‘z’ ending is held and attenuated like a violinist holding a high note and trembling it for dramatic effect.
Males use the sound in various situations — to advertise for a mate, to serenade a partner or, not infrequently, as an utterance that expresses annoyance. Ironically, in the following two recordings, one was delivered when a male Blue Tit spotted a Sparrowhawk drifting overhead; the other came from a bird that was accidentally disturbed from a roosting site in darkness.
Song given in response hawk: https://www.xeno-canto.org/211280
Song given in response to human: https://www.xeno-canto.org/618554
Telling male and female Blue Tits apart can be tricky. Not all males are brightly coloured with glorious ultramarine caps, wings and tail. Even watching a pair rearing young, it is sometimes only possible to be certain of the sexes because of behaviour — the female receives food from the male and she builds the nest, even though he gathers nest material before passing it to her.
