Not all birds start singing earlier due to climate change

Changes to the weather and the climate affect nature. Rising temperatures mean spring is starting earlier and autumn is starting later.

Not all plants and animals respond to these changes in the same way. For example, the first drumming by the great spotted woodpecker is now heard three weeks earlier than in 2001, the first chaffinch call is heard at about the same time as before, and the first melodies from the song thrush are now heard a week later than before.

Therefore, non-migratory birds have not all started ‘getting up earlier’ as global temperatures rise. Though one swallow does not a climate change make! And migratory birds who come to the Netherlands in the spring have so far shown little to no variation in when they arrive.

“Woodpecker, chaffinch of song thrush, they all respond differently to climate change”

Arnold van Vliet, biologist at Wageningen University & Research (WUR) and initiator of Natuurkalender.nl

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However, the response of plants and insects to climate change has been very clear-cut. Rising temperatures mean plants bloom earlier and butterflies and insects also appear earlier.

Warm winter

This year, it’s been another very warm winter. In January 2018, the temperature remained around two degrees higher than the usual norm for January, and October, November and December 2017 were also warmer than before. This year, the common hazel started to bloom in December – the earliest start in recorded history.

Great tit

The problems that differences in responses to climate change could cause are illustrated by a long-term study by NIOO-KNAW (the Netherlands Institute for Ecology) into great tits. Marcel Visser, one of the researchers involved in this study, addressed this problem during his inaugural address as an endowed professor at WUR. As a result of climate change, great tits are laying their eggs earlier. However, the moment of young great tits’ peak need for food is no longer corresponds with the peak availability of caterpillars, the principal constituent of the young birds’ diet. This is because the peak availability of caterpillars is now a little later in the year. An earlier brooding period therefore means that before and during the laying period, the great tit parents have to work much harder to find enough food, resulting in a drop in survival rates.

Phenology

To understand weather and the climate, you must track plant and animal species over a long period. A few years is not enough: you have to go back decades. Phenology is an interesting indicator in this regard. Phenology is the brand of science that researches annually recurring events in nature such as the moment when plants come into bloom, leaves unfold and fall, birds start to migrate and butterflies and other insects start to appear. You can also get huge numbers of people involved in this work, so it is a good research tool.

Nature’s Calendar

In the Netherlands, meticulously detailed plant-phenology reports date back as far as 1868. Furthermore, between 1940 and 1968, our country had an excellent phenology network. In 2001, research associates in Wageningen breathed new life into Dutch phenology by setting up Natuurkalender (Nature’s Calendar), an observational programme that focuses on spotting, analysing, predicting and communicating on annually recurring natural phenomena. As well as plants, trees and agricultural crops, the programme includes a large number of animal species.

Report observations

Via the Natuurkalender website (only in Dutch) anybody can get involved in these efforts by reporting the first snowdrop blossoms of the year, the first ducklings to hatch, the first barn swallows to appear, the first butterflies to spread their wings, or the first hedgehogs or grass snakes to emerge from hibernation. And you don’t need to be a nature expert. Everyone recognises some plants and animals, and you can also find plenty of examples on Natuurkalender.nl. By reporting your observations, you can monitor the effects of climate change in your own back garden or neighbourhood.

Help the study

By reporting your observations, you will help the research associates immensely. The more data, the better they can model the year and map out the effects of the weather and the climate on nature. The more observations are received, the more the differences between different regions can be examined and explained.

National Bird Census

Finally, here’s another tip. This weekend (27-28 January), Vogelbescherming Nederland (the Netherlands Society for the Protection of Birds) is once again organising the National Bird Census. This data is used to gain insight into how birds use domestic gardens. It’s a great opportunity to take a good look in your own backyard and see if you can find a species included in Nature’s Calendar!

Useful links:

• Nature Today keeps you up to date with all current events and developments in nature in the Netherlands and beyond.
• Nature’s Calendar
• Have you spotted an English oak, a common hazel, a European beech, a silver birch, a sour cherry or a small-leaved lime in your neighbourhood? If so, download the GrowApp, take regular photos of it and help climate scientists!
• Schools can also participate in the GLOBE Nature’s Calendar Campaign