In my column in March I wrote about using their very different songs to identify two similar-looking birds, Chiffchaff and Willow warbler. Two other spring arrivals, Blackcap and Garden warbler, present a variation on that theme – similar songs but they look very different. So, there’s no problem here then is there?

Blackcap male birds have a black cap and the female has a brown cap. A birding joke about Garden warbler is that their distinguishing feature is that they have no distinguishing features, being pale grey more-or-less all over. Both can be secretive birds, singing from deep within scrubby trees. With similar songs, identification becomes frustratingly less confident as leaves fill out and it becomes harder to see the birds. Having said that, the photo is of a Garden warbler I saw in late April, singing unusually prominently from the top of a Hawthorn.

Sometimes I need to give my head a shake and realise it’s the 21st century. In March I wrote about the difficulty of using words to describe bird-song and left you without a good solution for ID queries.

Here is a good option. Some friends introduced me to a smartphone app for bird identification - the Merlin ID app. It’s from the Cornell Laboratory of Ornithology in the USA, but it works fine for British birds too. I love the “Sound ID” option. “Get as close as you can, hold still, and press record” the app tells you. Well, the welfare of the birds is important so don’t disturb them. You don’t need to get so close for the app to work.

The app gives you a list of the birds it picks up, as it hears them. There are other sound recordings you can browse to match against the songs or calls you hear. There is also a thumb-nail picture to match against the bird, if you can see it.

The app shows sounds as a sonogram. These sonograms are like sheet music, representing sounds in a visual form. I write more about this in the longer version of the article we circulate to Wharfedale Naturalists Society members.

The app isn’t perfect though, sometimes “identifying” a bird when it isn’t actually present so it’s worth trying to see the birds too. Looking for the bird will help associate identification by sound and sight. “Getting your eye in” is about using information from different senses.