Seeing spotted crakes is always difficult. I was never all that hopeful of encountering one on my Girdle Ness patch - and if I did, I always thought it would be a briefly seen or flushed autumn migrant. The discovery of a singing bird in May 2016, in the cover of the relatively recently created 'marsh' in Nigg Bay, sparked a sequence of events that would see me spending unprecedented time watching, listening to, and learning about this relatively unknown species. It would also lead to a remarkable breeding record of this species, within 100 metres of a housing estate - only the 8th proven breeding record in the UK.  

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Introduction

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The area inland from Nigg Bay in Torry, south of Aberdeen, including the East Tullos Burn, has until recently been managed as an area of close cropped grassland and sports pitches, with rougher vegetation around the burn and regularly flooded areas. The East Tullos Burn project planned to rejuvenate the area, with the development specifically aiming to create wildlife habitats and a more accessible public space, in an area of sporadically flooded rougher grassland, with native trees filling the rest of the site. The wetland development consisted of meanders added to the existing path of the burn, with lots of planting of native wetland plants, and small areas of standing water designed to hold overflow from the burn during times of flood. These areas of permanent standing water are now well vegetated with banks of sedge and marsh marigold, small patches of reeds, and more open grassy patches around the patches of open water. 

 

The development began in March 2014 and the area was re-opened to the public during May of that year. Since the re-opening the wetlands have attracted a wide selection of birds. Mallard, moorhen and water rail bred in 2015, and the newly planted areas have proved to be valuable for species such as sedge warbler and particularly reed bunting, whose numbers in the area have increased notably since the development of the site. The wetlands have held occasional coot and ducks (e.g. tufted duck, wigeon and greater scaup), and rarer birds such as citrine wagtail and Tundra bean goose have occurred, but most birds do not linger in the area due to disturbance from dog walkers and children playing in the water.

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2016

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On Sunday, May 15th 2016 Andrew Whitehouse was birding on the headland at Girdle Ness, just north of the site, where he was told of a probable spotted crake in ‘the marsh’ by an unknown observer. Having contacted myself we met at the site and within an hour or so, had seen and heard a single spotted crake. Given the high levels of disturbance, and the small size of the site, we consider that the bird setting up territory was unlikely, and as such released news to the local text service, with requests for the news to go no further and for observers to view from the public footpath and refrain from using tapes to attract the bird. A small number of birders came down to the site and enjoyed close views of the crake on the evening of the 15th.

 

The next morning I received an email from Mark Sullivan who reported that an observer present at the site earlier that day had seen one crake well, along with getting very poor views of a bird that she described as being of a similar size and shape. I returned to the wetland that evening, and after a couple of brief audio and visual encounters with single birds, was treated to the astonishing spectacle of two spotted crakes flying around over the marsh. The two birds were seen frequently together through the following week, with frequent vocalisations, until they vanished almost without trace on May 25th. After a couple of weeks during which I’d been away from the area, I was delighted to briefly hear two short bursts of vocalisations on June 12th, confirming that at least one bird was still present. During my visits to the site, conversations with a local man who had been walking his dogs at night suggested that at least one bird was present from late April. Unprompted, I was approached and asked what the loud, repetitive ‘quick’ call was that had been coming from the wetland during the night. Shortly after, on an early morning visit, the same man waved and pointed in the direction of the wetland as a crakes song became audible. Further conversations with him revealed that the bird had been singing most nights, and the song was far crying and always the same repetitive note. Having had several discussions with him I have no doubt that he had been hearing spotted crakes at the site from late April.

As the site is so small and accessible it presented an excellent opportunity to study these little known and hard to observe birds. The necessity for a licence was raised with both the BTO and SNH, both of whom were comfortable with observations being made from the public footpath without the requirement of a licence. A number of interesting aspects of spotted crake behaviour were noted.

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Both birds vocalise

While unfortunately I don't have any recordings to verify this, both birds were heard to 'sing' at the same time at least once, and there were numerous occasions when the locations of calls from within the site hinted very strongly towards two birds vocalising, albeit not simultaneously. The idea that both males and females can vocalise is not particularly new, but I suspect that when confronted by a singing crake, most would assume that the bird was a male. RBBP records of this species are almost exclusively attributed to 'singing males' - can this really be stated confidently? Perhaps females only vocalise when paired up? Or perhaps all those recording 'singing males' have eliminated the apparently slightly softer vocalisations of females? Whatever is going on, at sites where more than one territory is suspected, there is potential for confusion caused by singing female birds.

Day time vocalisations

One thing I really wasn't expecting was to hear the birds during the day, but in fact it wasn't particularly unusual at all. I never heard full song during the daytime (this was mostly heard in the dead of night, or around dawn and dusk), but I did hear several variations on that theme in broad daylight. These can be broken down into three broad categories, as defined below. Another aspect of these vocalisations that really surprised me was that they were not always given from within the depths of the abundant cover - birds quite frequently vocalised in the open on the edge of banks of sedge or marigold,  in full view. This gave the opportunity to watch the physical effort the birds made with each sound, standing steady and compact, heads jerking downwards with each note. In fact, the birds were surprisingly confiding during the day, and allowed themselves to be filmed through a scope (under agreement from the relevant authorities of course) if you waited quietly enough.

Hesitant song

This was usually heard before dusk, and could feasibly just be birds warming up, or genuinely being hesitant about advertising their position while it would still be light enough for them to worry about diurnal predators. Hesitant song basically sounds just like the standard song, but is delivered for short bursts.

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Here, the bird threatens to get going a few times but without ever really managing it. Note how it never really finds it's rhythm too, with the pauses between notes being slightly extended from time to time. In this recording it's also clear that the singing bird doesn't enter immediately into full song, but starts off gently and ramps things up over the course of a few notes. This recording was made at around 10 pm, so late, but still fully light. The sonogram below is taken from this recording, showing the portion between 1:13 and 1:27. The 'ramping up' is visible here, with the notes noticeably reaching higher frequencies and getting louder (= darker on the sonogram) as the song progresses.

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Sporadic song notes

The most frequently heard daytime vocalisation away from early mornings or late afternoons was of single or double song notes, uttered quite loud, but without ever developing into song. Perhaps these calls are used as contact calls or alarm calls? Perhaps it's exactly the same as hesitant song but with the birds being even more cautious due to the time?

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Subdued song

Occasionally, during the day, birds would enter into what I have called subdued song. Here, a reasonable succession of notes are delivered, but the individual notes are given much more quietly, and never quite hit the same frequencies, or have the same quality as the full night time song. Note that the subdued song below was made from the same location as the other recordings, and the bird was at a similar distance (it must have been, as it was a very small site!). Perhaps this was the female bird singing? Whatever the reasons, you can barely hear it over the song of the skylark the my mic was pointing nowhere near, and was much further away than the crake.

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The breeding attempt

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With the prolonged presence of two birds, at least one of which was acting territorially, it was suspected that a breeding attempt had taken place. Evidence of this finally arose in unfortunate circumstances on June 16th. After a period of sustained heavy rain, much of the site became flooded. While walking along a path approximately 60 m from where the birds were most frequently seen, I discovered a predated egg (showing typical signs of corvid predation) that I didn't recognise. I took a series of photos and measurements which I supplied to Richard Castell (who literally wrote the book on British birds eggs), who responded confirming my suspicions that it was a spotted crake egg - and thus confirming breeding had taken place

 

2017  

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With the development of Nigg Bay into an extension of Aberdeen harbour, I'd been engaged in several strands of bird survey work, including monitoring for returning spotted crakes. All through late April, May and early June my 'listening sessions' drew a blank. It wasn't until 23rd June that a crake was heard singing at the site - again originally by the dog walker who first heard them last year, and then by myself the next night. This time the bird remained (or remained vocal) for only 8 days, and during this period it behaved more in the manner of a 'classic' spotted crake, with only nocturnal singing and nothing but strong, strident song. The bird was not seen at all during 2017, possibly due to the much higher and denser vegetation than from when the birds had been visible the year before. 

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