Irish Coastal NocMig Project

Coming April 17th!

Arctic Tern – Photo: Seán Ronayne

It is with huge excitement that I announce this project – something which I have been dreaming about for well over a year. It is well known that many coastal locations in Ireland act as a funnel for bird migration, of common species, and under certain conditions rare and scarce vagrants and/or migrants also. Because of this many birders visit such sites in spring and autumn to seek out migrants which have stopped along their journey. But what happens at night time: what’s going over and what are we missing? This is one of the questions this project hopes to answer! So let’s have a look at how we are going to do this:

Introduction

SM4 mini – Photo: Seán Ronayne

Sound recording as a particular interest within ornithology is booming, in part because of the fact that Covid-19 has forced people to look and listen to the birds they have around them during lockdown, but also as a result of the tireless efforts of certain bird sound enthusiasts, including the Sound Approach team (see: https://soundapproach.co.uk/): the pioneers of modern day bird vocalisation studies.

Sound-recording nocturnal migration is a phenomenon rapidly growing in popularity, and sheds some very interesting light on previously unknown nocturnal migration habits/routes of birds. It essentially involves leaving a microphone recording at night, pointing to the sky. In the morning, the audio is uploaded to software where one can scroll through the night’s recording and physically see whatever bird calls were recorded, in the form of shapes on a sonogram. These visually identified calls can then be played back, and the species identified, depending on the clarity of the call(s), which in turn is limited by a number of factors including distance and ambient noise levels.

Through recording and studying nocturnal migration, so much information can be extracted about bird populations and migration. One very famous example, at least amongst ornithological circles, is that of the recently discovered extensive overland nocturnal migration event of Common Scoter Melanitta nigra through the UK and Ireland in Spring (although the picture is much less clear in Ireland due to a lack of sound-recording), (see: https://www.birdguides.com/articles/migration/citizen-science-reveals-nocturnal-scoter-migration-routes/). This phenomenon was flagged up by the Sound Approach team, but a collective effort amongst UK sound recordists revealed an event on the 31st March 2020, which took place on a vast scale. Normally a strictly pelagic species, the newly discovered migration route came as a big surprise to many. This activity is now extremely popular in the UK and elsewhere in Europe; however, it has yet to gain momentum in Ireland, and, because of this, there is so much to learn. With Ireland being on the western frontier of Europe, it is an untapped resource waiting to reveal answers and possibly even hidden migration routes coming from Iceland and further afield.

Methods

Mizen Head, Co. Cork. Photo: banafshehr

A Wildlife Acoustics SM4 recorder will be deployed in the field for a minimum of one year, at an, as of now, undecided location at Mizen Head, Co. Cork – a well known bird migration point in south-west Ireland. The recorder will be set to record from dusk until 2 hours after dawn, allowing for the inclusion of early morning migrants such as pipits, wagtails, etc. At least one other station is planned, but this/these will be confirmed or otherwise at a later date.

Batteries & memory cards will be changed on a bi/tri-weekly basis. Data will be analysed using the methods laid out by the BTO (A Protocol for Standardised Nocturnal Flight Call Monitoring), and sound files will be analysed using Audacity. Weather data, as well as the time taken to analyse each night of recordings will also be documented. Any sonograms for publication online or elsewhere will be created using RavenLite. Count data will be filed in Excel and uploaded to irishwildlifesounds.com .

Any trends (as they arise) or interesting species will be shared online via the @SoundsIrish twitter account as well as on the Irish Wildlife Sounds website.

Discussion

The main idea of this project is to start uncovering nocturnal movements of birds in Ireland, in potential NocMig hotspots. There are so many questions to answer and I’m sure, many discoveries and surprises to learn along the way. This project has the potential to be very exciting. There is the possibility of recording some scarce or rare migrants given the long history of the site’s location or even just impressive counts of common species. It could of course be quite the opposite – it could be very quiet at night, but we won’t know until we try. If it is quiet then that’s valuable information also, and we will learn from this and try another location! But, the beauty of NocMig is that the machine does most of the the fieldwork for you. This has some seriously exciting implications. Could NocMig stations act as an ever-hearing supplement to bird observatories? And in the lack of a bird observatory, could a NocMig station obtain sufficient data to act as a pseudo-bird observatory? Let’s find out!