Timing is everything — for leaves, caterpillars and baby birds

So many plant–animal interactions have been harmonised over thousands of years but some of these relationships are now beginning to fall askew as a result of rapidly shifting seasonal patterns

Great tits have evolved to time the hatching of their eggs with the first flush of oak leaves, generally emerging now as April merges into May, ensuring an abundance of caterpillars to feed the chicks with

Each wild species has its own approach to keeping in tune with the seasons. Trees have ways to measure the intensity of sunlight and the ratio of daylight to darkness, registering environmental cues in order to know when the time is right to sprout new leaves in spring. It's not just as simple as measuring temperature and the span of daylight hours though. After an especially cold winter, for example, some tree leaves unfurl earlier the following spring. Conversely, after a mild winter, leaves can take longer to appear. Trees even have ways to calculate the number of milder days — what we might call an ability to count. By biding their time carefully, trees decipher the optimal timing to focus their energy on producing a whole new canopy of leaves for the growing season ahead.

In nature, as in life, timing is everything