This end of the year is widely regarded as a time of tradition. This can include the religious or spiritual traditions associated with Christmas and the winter solstice, family traditions like always watching It’s A Wonderful Life (I’ve still never seen it!), or local ones like knocking neighbours’ doors on Christmas Eve and ‘carol-bombing’ them with guitars, piano-accordions and tuneless but enthusiastic singing. Here at Forvie, it’s become blog tradition at this time of year to have a look back at the bird breeding season, now we’ve finally finished crunching the numbers and writing the reports. After all, nothing says Christmas like pictures of terns and fluffy Eider ducklings, right?
After the lockdown-interrupted 2020 season, it was a relief in 2021 to embark on the season’s work in circumstances of relative normality. However, the weather had other ideas. The spring was almost unbelievably cold, with snow during the first week of May. This meant we couldn’t carry out some of our routine monitoring work: the welfare of the wildlife must always come first, and flushing birds off their nests in cold conditions can be fatal for the eggs and young. Consequently some of our population figures for 2021 are best estimates rather than actual census data.
Later on in the season, when things finally warmed up, we were faced with another meteorological problem: drought. This wasn’t widely reported upon at the time, being that we’re somewhat off the beaten track here, but the fact was we had negligible rainfall for several months up until September, when the weather pattern finally changed. Normally, we’d be delighted with a dry summer, as dry weather helps the survival of the gull and tern chicks. However, this year the drought was so extreme that it nullified the effectiveness of the protective electric fence around the bird colonies. An electric fence requires a conductive ‘earth’ in order to complete the electrical circuit – and bone-dry sand doesn’t conduct. Consequently, the birds were beset by predation from the local Foxes and Badgers for the second half of the season.
But for all that, it was far from a disastrous season, and certain species fared very well indeed. Here’s how the key players performed in the long, hot summer of 2021…
Of all the breeding birds at Forvie’s ternery, the Black-headed Gulls are always the first to arrive, settle and get going. In 2021, this meant their peak egg-laying period, and consequently nest-census time, coincided with the May cold snap, so instead we could only estimate the population by looking in from outside. By these means we reckoned that approximately 1,500 pairs nested.
The first young began to fledge in early June, and a peak count of 1,099 fledged young was recorded at the end of that month. This peak count, of course, is a snapshot of the colony’s productivity, and the true total of fledged young is likely to have been substantially higher. All in all, another excellent season for this species, thus reaffirming the importance of the Forvie colony in a regional context. It’s now far the largest Black-headed Gull colony in the north-east (many other local colonies having declined or disappeared), and is a true stronghold for the species in our region.
These have bred at Forvie for many decades, and achieved a high level of breeding success over the years. In 2021 the first birds returned from their wintering grounds in South and West Africa in late March, and eventually 1,075 pairs settled on their favoured spot in the centre of the Black-headed Gull colony.
Fledglings were first noted in late June, and a peak count of 481 fledglings was recorded at the month’s end. In similar fashion to the Black-headed Gulls, other chicks would have continued to fledge after this, meaning the true total of fledged young would have been greater still. This represents a good solid season’s productivity, continuing the sustained success this species has enjoyed over the past few years. Forvie’s high productivity means that we ‘export’ birds to other colonies in the UK and wider Europe, thus helping the Sandwich Tern’s conservation status well beyond the boundaries of the Reserve. You can’t say fairer than that.
Arctic & Common Terns
These smaller cousins of the Sandwich Tern tend to arrive at Forvie a little later in the spring, with both species taking up residence from late April. Their nests and eggs are very similar in appearance to one another, so they are dealt with collectively when carrying out the nest census. This produced a combined total of 1,127 nests; feeding counts carried out later in the season indicated that the colony comprised c.91% Arctic and c.9% Common Terns.
Their breeding cycle being a month behind the Sandwich Terns, our Arctic and Common Terns were able to avoid the effects of the May cold snap. They did, however, suffer from the predatory attentions of Foxes and Badgers later on in the season (by which time most of the Sandwich Terns had already finished their season and departed). Consequently their breeding success was somewhat indifferent, with a peak count of just 195 fledged young recorded in mid-July. Overall a rather difficult and disappointing season, but certainly not a disastrous one.
These are our smallest, rarest and most fragile breeding tern species. In recent years their track record at Forvie has been poor, with multiple failures resulting from poor weather and predation – most recently in 2020 when a local Oystercatcher ate most of the eggs (you just couldn’t make it up). In 2021, 30 pairs attempted to breed, and the hatching rate was much improved… but then the Black-headed Gulls ate most of the chicks. If it’s not one thing stitching them up, it’s another thing: that’s life in the crazy world of Little Terns.
However, a minimum of two Little Tern chicks survived to fledge, giving the species its first breeding success here since 2018. Others may have done likewise, but no more than two fledglings were seen at any one time. Although this represents meagre productivity, it’s hopefully a step in the right direction. And yes, the sight of those two fledglings flying around the colony did elicit a fist-pump celebration.
This is another species with a rather forlorn recent history at Forvie, with a massive population decline allied to a long series of poor breeding seasons. It was to our surprise and delight, therefore, that they enjoyed a highly successful season in 2021.
In most years, the Eider nest census is undertaken in tandem with that of the Black-headed Gulls – so in 2021, in tandem with the Black-headed Gulls, it didn’t happen. Spring counts of Eiders on the estuary, plus observations of the comings and goings at the ternery, indicated that there were perhaps 100 or so nests within the electric fenced area, much the same as in other recent seasons.
Ducklings began to gather on the estuary during June, and by the end of the season in August a very respectable 167 had survived to fledge. This is the highest Eider fledgling count at Forvie since 2003 – an excellent result. The only minor frustration was not being able to explain the reasons behind this unexpected success story!
In summary then…
Forvie’s breeding birds have had better seasons than 2021. They’ve also had plenty worse. Despite difficulties along the way, all the key species produced at least some young, and some were very successful indeed. If I’d been offered that result at the outset, I’d have taken it!
That’s 2021 wrapped up then. Time now to look ahead to the 2022 season, which will be here before we realise it: the first Sandwich Terns might be back at Forvie within twelve short weeks. What a thought! I think I need another glass of sherry.