The shifts through your field season

"Repetition is mother of knowledge"

- as the saying goes.
Sometimes repetition is boring but necessary, sometimes it can be amusing. In field the seasonal repetition can be both.

After several visits to the same field locations, as my field studies include, you will not evade noticing the appearance and disappearance of organisms that seasonal changes bring. Insect species have their different peaks, plants start to flower other wilt and set seeds, the whole landscape change in colour, in short, phylogeny, as we ecologist call it.
This repetition is among the amusing ones I would say. In my case, as an pollination ecologist, the shifts in pollinator species and flowering plants is interesting to observe as they also depend on each other. Some pollinators, as many species of bumblebees, keep foraging and rearing young almost all the summer and consequently needs flowering plants all along. They can shift the species they visit, even if they have their favourite groups, but need them to be in enough numbers to be able to sustain their energy demanding flight and hungry larvae.
Sometimes, at least in some types of landscapes, this is not the case. Many late flowering plants do not appear in enough number and fewer pollinators may be sustained. This is noticeable when you visit several landscape types many times during the season.

A Common carder bumblebee (Bombus pascuorum) foraging on Brown knapweed (Centaurea jacea).

Also the peaks of the different guilds of pollinators can be seen. In May and June wild bees are very active but there are still quiet few hover flies. In contrast July abounds in hover flies but the wild bees are, especially at the end, not so abundant any more.
After some years of field work as a PhD-student working with insects one, at least I do, tend to remember and refer to different year as "a really good year for insects" or "that year there was very little activity. Could it have been the cold spring?" and so on. Well this year was in between I would say.
Yearly variation is an important concept in ecosystem function ecology as a factor affecting stability. Repeating measurements during a longer period can reveal interesting, and sometimes complex, structures in ecological systems. It can also lead to new questions to seek an answer to.

So the conclusion must be, I guess: even in field work, repetition is mother of knowledge.