Weak correlation between haemoglobin concentration and haematocrit of nestling Great Tits Parus major and Blue Tits P. caeruleus.

The article presents a study on the weak correlation between the hematocrit and hemoglobin concentration of nestling Blue Tits Parus caeruleus and Great Tits P. major. The researchers performed the study during the breeding season of 2010 as part of a long-term research project on the breeding biology of tits in Poland. They also used intra-class correlations to calculate within-brood repeatability. They found a significant positive correlation between hematocrit value and hemoglobin concentration for the nestlings of both species.