Nesting and the Long-tailed Tit
The Distribution of the Long-tailed Tit in the UK
The Long-tailed Tit is a relatively common bird. In 2020 they made it into the top ten of the RSPB’s annual garden bird watch, though they are more a bird of woodlands than gardens.
Outside of the breeding season they spend their time in small family groups of about 10 birds. Female young tend to move away to join other groups. The groups are territorial and maintain extensive territories, often 20 to 30 acres or more.
The groups form tight winter roosts – sometimes in tight rows along a branch, or in huddles, with the more dominant birds in the centre. These huddles help to maintain their body temperatures, and are critical for such small birds during cold spells. Fledgelings also do this for sometime after they leave the nest.
The recent mild winters have contributed significantly to the overall survival rate of the Long-tailed Tit and probably account for why this species is now high on the garden watch bird count.
Appearance and Behaviour of the Long-tailed Tit
Over the last three years we have occasionally seen them in Woodcock Wood. They are unmistakable – small and round with long tails moving energetically from tree to tree in search of insects and larvae, which form the main part of their diet throughout the year. They aren’t easy to photograph because they seem to be constantly on the move, searching one tree and off to the next.
Nest Building
In March of this year it was therefore great to spot a pair building a nest, albeit about 20 metres up in the crook of an oak bough. They may have been a long way up, but at least they were focussed on one place.
One of the oddities about their nesting behaviour is that they choose from a wide variety of sites. They regularly nest high up in oak and ash in the fork of large boughs, like ours. The nests will be camouflaged with lichen to match the growth on the tree bark. They occasionally choose conifers, or they will choose to nest low to the ground, in blackthorn or deep in brambles. Also, if a pair need to build more than one nest in a season, because of first nest failure, they don’t necessarily choose the same type of site.
The day we were at the wood watching them build, they had completed the main structure of the nest, and were at the stage of lining it with feathers. The pair would both disappear into the wood, and in a short time return with a large feather or two. One would enter with a feather, and the other pass its feather to the bird in the nest. They did this time and again over the course of the day.
Their nests are beautiful creations and totally fit for purpose. Constructed of moss, lined with hundreds of feathers, and bound on the outside with spiders web to provide huge strength and elasticity.
There can be more than 2,000 feathers in a single nest, and the insulation value is enormous – a very high tog rating!
The Abandoned Nest
We visited the wood about a week later. The nest was intact, and although we watched it frequently over the course of the day, we saw no activity at the nest. By the end of the day we assumed it has been abandoned. Whether or not this was the case we won’t know, but on our next visit the nest was hanging forlornly from the tree – a sad end to a beautiful creation.
In the classic study by Lack and Lack in Oxfordshire in the 1950s, the only successful nests were those that were hidden and protected by brambles and thorns. All of the nests high in the oaks failed. Later studies have shown varying results, as much depends on context, but the overall conclusion is that a very high proportion of Long-tailed Tit’s nests fail at some stage.
Social behaviour and the Perpetuation of the Species
A failed nest can lead on to several possible outcomes: the birds can start again at new site, the birds may make no further attempt at breeding and join the flock, or one of the birds may join another breeding pair and help the rearing of the young.
Invariably the helper joins a nest of a close relative, usually a sibling, and when a helper joins a nesting pair the probability of a successful outcome increases, which suggests that this behaviour helps the family’s gene to survive – success breeds success indeed, often on the back of failure!
Other Species That Utilise Nest Helpers: Azur-winged Magpie, European Bee-eater and the Dunnock
The average life span of the Long-tailed Tit is around two years. If a bird fails to nest in its first year, but helps to ensure a successful brood from one of its siblings, its contribution to the perpetuation of the species is achieved. This set me wondering about how this relates to the European Bee-eater and Azur-winged Magpie, two other species which utilise related helpers to raise young.
Three of the four species are gregarious and move around in family groups. The European Bee-eater has a life span of between 5 to 10 years, and the Azur-winged Magpie’s is between 15 to 20 years.
The imperative to help is likely to be driven by different factors. With the Long-tailed Tit and the Dunnock, it seems to be the perpetuation of the species through a social contribution. With the other two species, helping is quite possibly an apprenticeship of sorts …. something to follow up!
- https://woodcockwood.com/the-european-bee-eater/
- https://woodcockwood.com/eurasian-jays-and-azure-winged-magpies/
- https://woodcockwood.com/the-dunnock-the-most-extraordinary-of-ordinary-birds/
Elizabeth and David Lack
I cited the Lack and Lack study because this is one that is so often appears in the literature on Long-tailed Tits. It is a fascinating piece of work and has provided the foundation for the immense amount of research undertaken on the social behaviour of this species in UK:
- David Lack & Elizabeth Lack (1958) The Nesting of the Long-Tailed Tit, Bird Study, 5:1, 1-19,DOI: 10.1080/00063655809475897