Spotted Flycatcher

To hear something like the nocturnal flight call of Spotted Flycatcher during the day, you need to pay attention in late spring and early summer, when they are singing. This is easier said than done, because their song is one of the most inconspicuous and high-pitched in the woods. Older listeners may have trouble hearing it at all. In the song, there are elements that share several peculiarities with NFCs used in both spring and autumn. Once you get to know the song better, their NFCs may sound a little more familiar.

Spotted Flycatcher arrives rather late in Europe, with the bulk of the population arriving in May and some only in early June. In the north this means that by the time they are arriving, nights are very short, and they may need to complete their migration flights by daylight. At Kabli in Estonia in late May, Margus Ellermaa has recorded flight calls while confirming identification visually. These daytime recordings helped us eventually to crack the nocmig code for this species, since Spotted Flycatchers use the same flight calls at night. Our previous assumptions about Spotted Flycatcher NFCs had been based on calls more frequently used during the day, but not in flight, and those turned out to be incorrect.

The flycatchers are a group where sonagrams are particularly helpful for identification, but with practice it does become possibly to identify most calls by ear.

seep calls

• duration 76 – 130 ms (90% range, median 102 ms; n = 142)
• frequency range 4.3 – 8.5 kHz (mean min 5.6 kHz; mean max 7.1 kHz; n = 142)
• at least two frequency bands, but closer recordings often show three or four; two main bands typically spaced about 1 kHz apart
• usually sounds ‘level’ (see example a), though majority are slightly descending overall (b, d, J & l); some calls are shaped like a shallow U ( f); fewer are arched (e); some rise in pitch (h).
• diagnostic feature: majority of calls have spikes extending upwards, nearly always towards the end of the call; average per call is 1.5 spikes; 39% have none (a, e, f, g & h), 25% have 1 (b, d & l), 15% have two (c, j), etc; max counted is 9 spikes (n = 142 calls).
• calls with more spikes have buzzy or harsh quality (k)

Effects of recording quality

• At close range, more bands may appear (we have seen as many as six).
• In distant calls, spikes may be much harder to detect, and calls may appear shorter than they really are as fine details (darker blue on our sonagrams) disappear.

• European Pied Flycatcher Ficedula hypoleuca NFCs show fine, tooth-like modulations throughout, not spikes, with the deepest ones at the start of the call. They also average longer and more arched or curved. Pied usually ends with a steep descent, whereas Spotted is more likely to have an upward spike at the end.
• European Robin Erithacus rubecula NFCs are higher-pitched and shorter, with bands that are less flat, and show more kinks and steep angles. They rarely show any fine modulations; if any then only on the lower band.

• anywhere: over towns, forests, mountains, offshore
• mainly nocturnal: very occasionally migrates by day, mainly in late spring
• can be expected at any hour: a bias of activity towards second half of night

We intend to make further studies of diurnal flight calls in order to learn more about the range of variation in visually confirmed flight calls. A problem for the future will be to distinguish Spotted Flycatcher from Mediterranean Flycatcher M tyrrhenica, which breeds on the Balearic Islands, Corsica and Sardinia. In parts of North Africa and southern Italy both Muscicapa species can be expected on migration. In addition, Spotted Flycatchers breeding in Iberia and North Africa differ genetically from those in the rest of Europe (Pons et al 2015), and we should be alert to the possibility of vocal differences, however subtle, between these two groups.

The Portuguese examples given here probably include migrants from both Iberian and northern European populations of Spotted Flycatcher but are very unlikely to include Mediterranean Flycatcher.

Pons, J-M, Thibault, J-C., Aymí, R, Grussu, M, Muntaner, J, Olioso, G, Sunyer, J R, Touirhi, M & Fuchs, J 2015. The role of western Mediterranean islands in the evolutionary diversification of the Spotted Flycatcher (Muscicapa striata). J Avian Biol 46: 1-13.