[not in handout, see intranet]
Norton-Griffiths (1969) - the intermediate case of the Oystercatcher
This species is nidifugous, but not self- supporting until fully fledged
1. The infants take food from the parents' bill- tip
2. The young follow the parents out to feeding grounds.
3. Parents are careful always to open up mussels and crabs which they bring.
4. Young “learn from their parents to recognize bivalve molluscs, and the techniques for eating them.”
5. Age when parental feeding ceases is very variable. (Record was still being fed 43 weeks after hatching)
6. Learning depends on practising on food left by parents.. In shallow water, when mussels are open one method is to stab through with beak prevent the mussel from closing. Alternatively, with closed mussels in dry patches, they are pulled off and taken to a piece of hard sand, and then shell is broken at the side. Adult birds tend to specialise in one or other method, and offspring appear to learn the method favoured by their parents.
7. There appears to be a high infant mortality rate due to birds who fail to learn to open up shell fish.