Bird of Interest 9 – Great Tit and Recent Research

The numbers of Great Tit populations tend to fluctuate in parallel with Blue Tit populations and with the numbers in other populations of other passerine species. The breeding season is short for this species, with the majority of the birds having only one brood. The date of egg-laying has varied by over a month in different years, this fluctuation being in parallel with that of some of the more common caterpillar species. It seems probable that both Great Tits and caterpillars are affected by a third factor, possibly the opening of the oak leaves, since there is a good correlation between the mean date of egg-laying and the temperatures in spring (Perrins 1965).

The analysis of distances between neighbouring Great Tit nests showed that nest sites were more spaced out than would be expected from a random distribution; this indicates that interactions between the birds produces a local density-limiting effect on nesting sites. In two successive years, established territorial pairs become removed from a stable spring population in mixed woodland. These removed birds become rapidly replaced by new pairs. These newcomers were largely first-year birds; they come from territories in the hedgerows that surround the woodland; the vacated hedgerow territories are not refilled. The hedgerows are found to be sub-optimal in terms of reproductive success. Thus territory limited the breeding density in this optimal habitat for Great Tits (Krebs 1971).

The Eurasian Sparrowhawk is a predator of Great Tits, with the young from second broods being at higher risk partly because of the hawk’s greater need for food for its own developing young. The nests of Great Tits are raided by Great Spotted Woodpeckers, particularly when nesting in certain types of nest boxes. Other nest predators include introduced Grey Squirrels (in Britain) and Least Weasels, which are able to take nesting adults as well (Dunn 1977).

Reference List

  • Dunn.E., (1977). “Predation by weasels (Mustela nivalis) on breeding tits (Parus Spp.) in relation to the density of tits and rodents”. Journal of Animal Ecology, 46, 633–652.
  • Krebs.R.J., (1971) Territory and Breeding Densities in the Great Tit (Parus major). Ecology, 52, 2-22.
  • Perrins.M.C., (1965) Populations fluctuations and clutch-size in the Great Tit (Parus major). Journal of Animal Ecology, 34, 601-647.

About Thomas Whitlock

I'm a third student at the University of Reading, currently studied for a degree in Zoology. I have a wide interest in biodiversity, most notably British wildlife. I have an especial interest in British mammals and birds. I hope to become a wildlife cameraman or photographer after I graduate, and I feel that blogging will be a key component of any future job in Zoology. This is my first blog, so please be kind!
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