State the relative use of the habitat by the Great Tit in the upper crown of the tree close to the trunk.

Identify the section of habitat used least by the birds.

Compare how the Varied Tit and the Marsh Tit use the habitat in the upper crown of the tree.

State how the distribution of birds changes with their size in the middle crown of the tree.

Suggest one reason why few Varied Tits were found far from trunk.

Discuss whether the results for the Varied Tit and Coal Tit indicate competitive exclusion.

medium to low

lower crown, far from trunk

smaller birds make more use of the habitat further from the trunk / larger birds make more use of the habitat closer to the trunk

their food is close to the trunk / fewer predators close to trunk / too big for small outside branches

Accept any valid suggestion.

a. the competitive exclusion principle states that no two species can coexist if they occupy the same niche/compete for the same resources;

b. competitive exclusion is supported as there is little overlap between the two species in the habitat;

c. competitive exclusion is not supported as there is some overlap between the species;

d. we do not have enough information about the resources required by each species to say if competitive exclusion is occurring;

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.

Some candidates simply did not read the questions with sufficient care and answered about sections of habitat that were not asked in the individual questions. Few candidates had difficulty stating the relative use for the Great Tit, but some did not address the two parts of the expected answer; some did not understand that the white spaces in the row of "bushes around trunk" were for lack of data, not "low" relative use. Most could compare the use of the habitat well although there was some difficulty in making clear, concise comparisons. Most could state how the distribution changes, but some in a very convoluted manner. Most candidates gave reasons as to food availability or the weakness of outer branches for heavier birds but some seemed to have understood the question the other way around. There were a considerable number of candidates who had a general understanding of competitive exclusion by realizing there is little overlap between the two species in the habitat, but only a few could define it correctly or provide opposite arguments.