This year (2016) I've been lucky enough to be a part of a few Firecrest Surveys with Gwent Ornithological Society to establish how many breeding pairs are in Gwent. This location is pretty well protected but despite that, it still remains disclosed. As you can hear in the recording, it starts off with a Goldcrest which was the intended subject for the sound recording. The Goldcrest was then joined by a Firecrest which not only added a new location to the survey map, but actually gave me a great opportunity to directly compare the two-very similar species-side by side.
Firecrests are Schedule 1 birds, and should not be disturbed in any way shape or form, especially during the breeding season. This however was one of those special moments that I couldn't take back even if I wanted to.
Firecrests have a less rhythmic and melodic song, only very slightly change pitch from start to finish (monotone). They have no fancy flick at the end of their song either and can sometimes be hard to pick out simply because they fade in and out seamlessly from silence.
Goldcrests are bold, rhythmic, complex and quite often end with a fancy flick. This flick is not always present but when it is, it's a fast trill, easily missed, but a key feature none-the-less.