Wildlife research is unusual among sciences in that the experiment cannot be scheduled. Data collection happens when the animals do something, which is often a few weeks a year.
The animal sets the window
Breeding, migration, denning and hibernation each occur within limited periods, and the observation a study depends on may only be possible during one of them.
Miss the window and the wait is a full year, regardless of funding, staffing or how much preparation was completed. There is no way to compress it.
This is why so much wildlife fieldwork happens in a compressed frenzy followed by long months of processing samples and data indoors.
Sample size accumulates slowly
Statistical power in a study of a long-lived animal requires observations across many individuals and, more importantly, across many years.
A single season can be unrepresentative because of unusual weather, a food failure or a disease event, so conclusions drawn from one year are fragile.
Meaningful results about survival and reproduction therefore often require a decade of consistent effort, which is longer than most grants and many careers at one institution.
Funding cycles do not match
Research grants commonly run a few years, which is enough for a short study but not for the long series that population questions demand.
Researchers respond by chaining grants together, running the same site under successive funding sources and absorbing gaps with volunteer labor or institutional support.
Long-term datasets that survive this process are disproportionately valuable, and they usually exist because one person defended them through repeated funding gaps.
Logistics consume the budget
Reaching a study site can require aircraft, boats, permits, vehicles and housing for a crew, and those costs are incurred whether or not the season yields data.
Weather can eliminate access for weeks, and equipment failures in remote locations are not quickly fixed. Contingency is built into every field plan.
Because the fixed cost of getting there is so high, researchers collect samples for questions they are not yet asking, banking material for future work.
Careers are shaped by the calendar
Graduate programs are structured around a fixed number of field seasons, which limits how ambitious a thesis question can reasonably be.
A failed season is not a setback of weeks. It removes a full observation year from a degree with a limited number of them available.
The practical consequence is that study designs are chosen for the risk of missing a season as much as for the interest of the question.