What Nature's Calendar has to say about spring

Does Spring 2017 feel memorable?

For me there have been some odd moments, like having to water my bone dry garden and simultaneously protect it from frost. Also it feels like I have been basking in the heat one week and then feeling the chill the next.

But what are the finer details? What is Nature's Calendar telling us about spring so far?

Weather

The MET office summarise the months between December and February as ‘dry and mild’, around two degrees warmer than the average.

This is a rather unusual combination because we might normally expect winters to be relatively mild and wet due to low pressure, or cold and dry due to high pressure.

March was also close to two degrees warmer than average and dry in some areas.

April was half a degree warmer than average overall. Many of us will still remember the unseasonably scorching weekend of 8th/9th which was followed by the extremely chilly final week of that month. Rainfall continued to be low in most areas.

What might we expect to see from Nature’s Calendar records?

A dry spring wouldn’t really show up in the kind of records we collect, although clearly it is not without impact; dry ground must make it harder for species like blackbirds to collect worms to feed their chicks.

However, the effects of a drought later in the year would be picked up in our records as it can result in earlier leaf tinting.

Snowdrops are a useful indicator of the season (Photo: Amy Lewis / WTML)

What did we find for snowdrops?

Date of first flowering snowdrops seem to be a useful early indicator of the season; they are often recorded prior to Christmas now in mild years. I’ve compared early season snowdrop records between this winter and the one before.

Date

No. of December records

No. of January records

Overall average date

Dec 2016 - Jan 2017

3

378

29 January

Dec 2015 - Jan 2016

26

767

23 January


December 2016 to January 2017

In December 2016 we had a handful of records but numbers picked up by January.

December 2015 to January 2016

This was a markedly different season with 26 December records and a massive 767 January records. Overall average flowering date was just under a week earlier.

This is perhaps not a total surprise since you may recall December 2015 was record-breakingly mild (5 degrees warmer than average) and no doubt gave the January flowering snowdrops a head start too.

Spring 2001 is the year we use as a benchmark (because temperatures were similar to the 30 year average) and 4 February was the average flowering date for snowdrops that year so in fact both of the last springs have been relatively early for this species.

Snowdrop seems impervious to wildly varying winter conditions, compared to spring blossom that is frost sensitive, it does not seem to mind being frozen whilst in full flower so early flowering is unlikely to have much adverse impact on it.

What about mid- season spring events?

I then took a look at some mid-season spring events where most 2017 records should now be in. I compared these dates with both 2016 and our benchmark year of 2001.

Event

Average date 2017

Average date 2016

Average date 2001

Hawthorn first leaf

15 March

8 March

3 April

Rook first nest building

3 March

4 March

12 March

Brimstone butterfly first seen

19 March

4 April

9 April

Frogspawn first seen

1 March

4 March

12 March

Spring 2016 overall was not as warm as spring 2017 and this is borne out by the records, all events (except hawthorn first leaf) are earlier this year than for 2016.

However dates in both 2016 and 2017 were still earlier than our benchmark year of 2001.

Frog spawn, a remarkable spring event (Photo: Christine Martin / WTPL)

What we've learned

This feels like a season of two halves so far: snowdrops were later than the winter before (the record breaking Dec 2015 probably having an influence) but most other events were earlier due to the relatively mild weather during 2017.

There are still later spring events you can look out for, like oak and ash leafing in northern areas plus flowering dog rose and grasses.

Keep your eyes peeled for nature's events and let us know the dates you see them on the Nature's Calendar website