We're concerned when it's cold – kicking up the snow to reveal the soil below for the hungry-looking European Robin during a walk in late February, and thinking about Cetti's WarblersEuropean Stonechats and Eurasian Wrens in the weeks and months that follow.

We eagerly await the arrival of migrant species – predicting what will be back 'on patch' at the weekend and remarking on anything out of the 'norm'. We can't help it – it's these questions that keep birding so fascinating!

The BirdTrack reporting rate graphs are certainly keeping many of us interested here at the British Trust for Ornithology (BTO) HQ – comparing hearsay with the graphs to see if this year's records are on par with the historic reporting rate. Do the numbers look below average? Did migrants return late?

Here in south-east England at least, it felt as though Common Whitethroats were pipped to the post by Lesser Whitethroats. A quick glance at the BirdTrack reporting rate for England shows that the two arrived around the same time.

The consensus on social media is that House Martins and Common Swifts are back, but in much lower numbers than previous years. Is this reflected in data collected using complete lists in BirdTrack? On the latest UK-wide House Martin graph from BirdTrack all looked to be going fine, but the last fortnight shows the reporting rate to be well down on the historic average. Is swift late or down on previous years? Only the data can reveal this.

house martin

All in all, early signs are concerning for some species, but there is only one way to find out how both our commoner resident and migrant species have fared between 2017 and 2018: the Breeding Bird Survey (BBS) results. Published a couple of months earlier in 2018 than previously, it is hoped the 2017-18 year-on-year trends will be released in early 2019, once data have been entered for the current year, checked and trends calculated (which takes more than a month to do!). These should provide some interesting reading.

Despite the hints from BirdTrack, feelings from birders in the field and trends from BBS, the results won't tell us why some species did well over winter and others did not – we can only leave that to further speculation!

Written by: Sarah Harris & Scott Mayson, BTO

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