Herring Gulls

Problem : How do Herring Gull Chicks know where to Peck for Food?

Lets Try to Set Up an experiment to find out its Answer

Any Ideas?..............

Here is one observation that might help you solving this problem

The babies peck at red spot, of their parent’s bill which induces them to regurgitate food for them.

Is that answer? NO ……. The question still remains unanswered……..

Rather a new question arises?

Now we need to discover whether naïve gull chicks are born with built in preference for long yellow things with yellow spots?

Lets put on some wild guesses ……………………..

Guesses

What Niko Tinbergen Did?Who is this man?..................

He is the scientist who answered this question

Not only answered this question but also told us how to solve similar behavioral problems

What he did was he planned a brilliant but very simple experiment ,Lets see what he did.

He offered young chicks a range of DUMMY cardboard gulls head varying in bill spot and color.

For each combination , he measured the preferences of baby chicks by counting their pecks in standard time.

Wow, then what were results? ........................Conclusion?

Then what we have to learn from this?

It’s the method he used……

And the pitfalls that u must avoid to get correct results

These turn out to be very general Principles which we can apply

every whereHow many chicks should be tested? 1 or 2 or 3……

Off- course more than one…. But why?

It could be that some chicks are red biased,Others are blue biased, Or with no tendency in general to share any favorite color.

Then how many we should Test?Is Two enough? Or Three will do?

Lets see, try some statistics

For 2 chicks ,There 50% of chance that first chick chooses red spot,And also 50% chance of 2nd chick choosing red spot randomly. (Even if they r colorblind)

This means that 50% chances of both chicks will agree …..

Then 3 chicks?

No, similarly there is 25% chance of unanimous verdict (Just by chance)

How about 12 Chicks?

Now you’re talking .

If they r independently offered a choice between two alternatives,The odds that they will reach same verdict by chance will quite low,Only one in 1024

Now we have to decide how to test the chicks?

Test them as group? Or Individual?

Suppose ,We tool group of 12 chicks and give them options of pecking red or blue spots, and measured the pecks and (fortunately)? Results were 532 pecks at Red and 0 pecks at blue….

Dose that show that have strong tendency of pecking Red?

Absolutely NOT

They could have tendency to imitate themselves. As domestic chickens do…

The 12 chicks together are strictly equivalent to a single chick, and their summed pecks , however numerous, resembles only one peck by one chick.

So all chicks should be tested INDEPENDENTLY

Lets try one more question?How do Adult Gulls know that this is egg and is SUPPOSED to be incubated?

Tinbergen's four questionsHe is well known for originating the four questions he believed should be asked of any animal behaviour, which were:Proximate mechanisms:1. Causation (Mechanism): what are the stimuli that elicit the response, and how has it been modified by recent learning? How do behaviour and psyche "function" on the molecular, physiological, neuro-ethological, cognitive and social level, and what do the relations between the levels look like? (compare: Nicolai Hartmann: "The laws about the levels of complexity") 2. Development (Ontogeny): how does the behaviour change with age, and what early experiences are necessary for the behaviour to be shown? Which developmental steps (the ontogenesis follows an "inner plan") and which environmental factors play when / which role? (compare: Recapitulation theory) Ultimate mechanisms:3. Evolution (Phylogeny): how does the behaviour compare with similar behaviour in related species, and how might it have arisen through the process of phylogeny? Why did structural associations (behaviour can be seen as a "time space structure") evolve in this manner and not otherwise?* 4. Function (Adaptation): how does the behaviour impact on the animal's chances of survival and reproduction?