Far from it: field study of animals is a complex matter that calls for special knowledge and techniques, partly because researchers have to adapt to the specific requirements of the species in question. But it’s also a very satisfying activity.

Studying animals has been a fascinating and engrossing question since ancient times. Field studies need to be conducted to understand the behaviour and ecology of animal species, and so research techniques have had to be designed and fine-tuned. Today these allow us collect information both for scientific purposes and for much more practical reasons like management and conservation of species. 

Carrying out a complete survey of a species is a complex matter but abundance estimates can be carried out using a range of counting techniques.
They have to take important factors into account, such as the ecological characteristics, behaviour, density and contactability of the population under study, but also the features of the area where the survey is to be conducted.

Where a complete estimate of population abundance is impossible, for example in the case of elusive species or difficult terrains, a relative abundance index can be used, which does not yield actual abundance but is indicative of it and can be useful for monitoring population trends over time.

Making unique identification of individuals of a given species is useful both for estimating the total population abundance and for studying their ecology and behaviour. However, recognising individuals animals relyingbased on their natural physical appearance alone is a very complex if not impossible task.

Ringing is a simple method allowing individual marking of birds. It involves tagging the birds with a metal or plastic ring placed around their lower leg (or tarsus).
Each ring has an alphanumeric code that allows individuals to be clearly identified.

The individual is captured using whatever method is appropriate for the specific species and tagged with a ring. Various biometric measurements are taken and the bird is then immediately released.
Metal rings require recapture of birds for code reading but have the advantage of being all but indestructible.

Coloured plastic rings, on the other hand, allow remote identification of the bird without recapture, by reading the code and associated colour visually using binoculars or a camera.
Individual marking of birds allows study of migration, behaviour and social structure, longevity and survival rates, reproductive success and population growth.

Ankle straps would not be appropriate for use on mammals since they could be removed by the animals and so alternative marking methods are used on other parts of the body.
Medium-to-large mammals are normally marked using tags applied to the ear cartilage or plastic collars in various colours and sizes, bearing one or more characters or combinations of colours.

Here again the animals do not need to be recaptured to read the markings and identify individuals since this can be done remotely using binoculars or a spotting scope.

Arctic terns are captured using special drop traps that can be activated from a distance.

Once the bird enters the trap, the support that props it open is pulled away to close it.

The tern is then immediately recovered by the surveyor...

...and tagged with a coloured plastic ring on one leg and a metal ring on the other, which are checked for comfort.
Next, biometric measurements are taken to obtain important information on the health of individual specimens as well as on various population characteristics.

First of all the tarsus – the featherless lower leg between the foot and mid-leg joint – is measured using a simple calliper.

The head-beak length is then measured from the point of the beak to the neck, followed by the beak length and finally the beak thickness at its top end.

Special rulers are used to measure the wing chord, i.e. the full length of the wing, bent at a 90-degree angle, from the most prominent point of the wrist joint to the most prominent point of the longest primary feather.

Now measurement is finished and the tern can be set free!

Some kinds of studies may require biological samples to be collected directly (blood, feathers) or indirectly (faeces, regurgitate).
Biological samples enable potentially dangerous diseases to be diagnosed in a population, as well as for the genetic characteristics of its members to be examined, also determining how these characteristics are transmitted to offspring. Finally, they can be used to analyse the diet of a species.

Blood sampling is a relatively commonly used technique. It requires experience and care as well as suitable equipment but can provide a range of information through health, genetic, and immune-system analysis, determining how well individual animals can respond to potential pathogens. 
Sampling needs to be done followsing a specific procedure or ‘protocol’ for a given species, ensuring both the welfare and safety of the animal, as well as the safety of the person taking the sample. The protocol specifies, among other things, where (from which blood vessel) and how the sample should be taken.

Biological sampling of faeces can be conducted in an absolutely non-invasive manner. This enables a wide range of often important information to be obtained. Naked-eye and microscope examination allows analysis of both health status of individuals, for instance by detecting the presence of parasite eggs, and the feeding habits of the species in question by identifying hard matter in the sample. Furthermore, although DNA analysis of faeces is complex due to the high degree of degradation, it can yield even more detailed dietary information.
Because faeces can contain excreted metabolites from stress hormones such as cortisol, more complex analyses can be conducted for behavioural studies examining stress response.