Starling Murmurations

Starling Murmurations

Coilin Mac Lochlainn reports on the winter phenomenon that is a Starling Murmuration

I went to Nobber, Co Meath, on February 6th 2019 to view a starling murmuration and to try to understand what it was all about. This one had attracted a great deal of attention since the beginning of the year, even making it onto RTÉ’s nightly news.

A murmuration is a gathering of tens of thousands of starlings as they go to roost each evening at a favoured woodland or reedbed during the winter. But before they alight, they perform spectacular aerial manouevres, in unison, for some fifteen or twenty minutes as the light fades.

In Nobber (from the Irish ‘An Obair,’ meaning a place of work), their roost is a dense conifer plantation in a grassy hollow just south of the village. I took up position at a point above it with a good view of the surrounding countryside. Others were also there to watch: one man told me he had come from as far afield as Bray, Co Wicklow.

Although I arrived early, I failed to see the initial formation of the main flock: it was already very large when it materialised on the horizon to the south, so it must have assembled some distance away. Within minutes it was passing overhead, a sea of small birds moving in silence except for the swishing sound of thousands of fluttering wings. In this respect it differed from murmurations of rooks and jackdaws I have seen, as these birds call continuously; in the case of jackdaws their unbroken chorus of ‘chucks’ and ‘chacks’ sounds almost musical, an effect that may be intended or have purpose.

Even as the starlings began their manouevres, more continued to stream in from all points of the compass, in groups big and small, joining the main flock as it swirled above and around the roost across an area spanning three or four kilometres of rolling pastureland, an area of battlefield size in the days of yore.

Presumably, given their numbers, the starlings were coming from locations anything up to sixty kilometres away, maybe more. Flying at tree height or hugging the ground, they zipped in at speed, making a beeline for the plantation but then continuing to join the main flock.

A murmuration is spellbinding. The flock twists and turns in the sky like a huge shoal of fish in the sea. It can balloon, then contract into a ball; rise, then plunge towards the ground; or billow like smoke. It can stretch like elastic, forming a narrow band that moves in a wave then reverts to a ball again.

The seething, plastic mass of birds, writhing in the sky above the roost, is like an amoeba viewed under a microscope, pushing out plasma in foot-like protrusions that it then withdraws like a sea anemone retracting its tentacles.

Satellite flocks peel off or are pinched off, but soon rejoin the main body, melding back in, somehow avoiding collisions. This happens repeatedly, with several flocks at times performing at once; sometimes breakaway groups of just fifty or so birds keep on displaying as though they were still part of the group…and then rejoin.

The whole enormous gathering follows an unplanned itinerary with the birds using the roost site as a fulcrum to roughly circle round, covering several kilometres in just minutes.

It is a mesmerising spectacle. I would describe it as a flock coherently and intelligently swirling, ballooning, contracting, rising, falling, turning, flowing, billowing and merging, and never losing contact: the birds seem magnetically connected to one another, even when a group breaks loose and is lost for a while in an ancillary display of its own. It is an edifying and heartwarming sight and you cannot help but think the birds see it that way too.

The physics of how they do it has not been fully explained; there seems to be more to it than birds simply responding to visual cues from the seven birds nearest to them, as often quoted in explanation. The murmuration has no leaders: it is a team effort governed loosely by some inbuilt or systemic sense of rhythm or coordination.

It may have its evolutionary origins in the shoaling behaviour of fish; it is also possible that the evolution was convergent, with similar behaviour evolving independently in fish and birds.

The question of how they do it generally takes second place, however, to the question of why they do it. Observers usually want to know not how it is done (because it seems almost miraculous) but why they engage in this kind of behaviour at all.

Again, this has not been satisfactorily explained, though some suggested reasons are frequently touted. The first is that it is a survival strategy to discourage or disorientate aerial predators such as peregrine falcons. Certainly, there is safety in numbers, and the greater the number, the safer the birds, so it makes complete sense for birds to roost together to reduce the predation risk. But if avoiding falcons were a murmuration’s aim it would make better sense for the flock to go to roost immediately and not remain in the air for twenty minutes. Murmurations attract birds of prey, so if avoiding them is the purpose then why murmurate?

A second hypothesis is that roosting in flocks helps the birds identify which of their fellows have been feeding well so they can follow them to the same food sources the next day. Whatever the truth in that, it would be easier to accomplish it at roost than in the sky. How could a starling keep its eye on another in a whirling flock of 50,000 birds or find it when it went to roost? Any find-and-follow behaviour would work against synchronised aerial movements and upset the display.

It’s hardly conclusive, but I put out bird food for my garden birds every day throughout winter and plenty of starlings visit my garden, but their numbers do not grow visibly as the days go by.

I would allow, however, the possibility that starlings pick up information on food availability from others in an organic way. They cover so much ground in a day that they don’t miss anything of relevance to their survival.

A third and often-heard explanation is that starlings murmurate for the sheer joy of it. This is not as unlikely as it may seem and it could hold the answer, at least in part.

When this possibility is put to experts some say it is anthropomorphic to think that starlings have fun. We are simply projecting our human feelings onto them, they say.

But hang on a minute…if fun and laughter is natural to humans and fulfills some psychological role, isn’t there at least a chance that starlings can also have fun and benefit from it psychologically? Perhaps the benefits extend to their overall health and wellbeing.

With that in mind, I took a closer look at the murmuration in Nobber as it played out before me. I was struck by one astonishing move where the flock plummeted towards earth at breakneck speed but turned at the last moment and shot back up, fanning out like an exploding starburst firework. Why would they do that except for the sheer exhilaration of it?

During winter, starlings spend all day searching for food, beginning at first light even on the coldest days. It must be a welcome respite from the daily grind to come together at day’s end to murmurate. It is not an activity exclusive to starlings: other birds do it too, including most notably dunlin, knot, jackdaw and rook.

Another species that murmurates, after a fashion, is us humans. Spectators at football matches practice the ‘Mexican wave,’ revelling in the visual drama of it and the camaraderie it engenders. We experience it too in military drills, in marching bands, at rock concerts and in gospel singing. These are so much fun, but why? And to what end?

I think it all springs from a primal urge to bond: we have an instinct for bonding, for tribalism. This extends beyond family to the collective: our crowd behaviour, whether it be song or synchronised action, fosters a sense of cohesion and security amongst members of a community, a tribe or any geographically-linked society. It is emotionally and spiritually uplifting; it is life-affirming. Therefore, we engage in these behaviours en masse. The more of us there are assembled in a place, the more likely we are to come up with a chant or pick up on a chorus.

These feelings are not beyond the reach of starlings, or birds in general, in my opinion. I detect them also in the animated chirruping of house sparrows as they settle into their roost in a thicket of a winter’s evening. I sense their desire to bond with members of their tribe, in the same way that starlings do by murmurating, or we do by chanting. Such behaviours help birds weather the cold and other deprivations of winter.

I suspect it was also critical to the well-being of passenger pigeons, which swarmed in flocks numbering millions, darkening the skies. When their numbers fell catastrophically through exploitation for New York food markets, they could no longer carry on and eventually died out.

In Nobber, the starlings finally descend on the plantation and break into loud chattering and squabbling as they jostle for the best places in the roost, surely at a premium given the small size of the plantation and their overwhelming numbers. Gradually they fall silent and darkness falls.