Nest function in birds

Over the past few years, Dr Charles Deeming has been developing a project looking at nest function in birds. Working mainly with Blue Tits and Great Tits and in collaboration with a variety of people, Charles has been furthering our understanding of the factors that impact upon reproductive success.

Jennifer BrittIn early 2011 Jennifer Britt’s study into the relationship between nest composition and environmental temperature, carried out as an undergraduate UROS student, was published in Bird Study. This was the first study to suggest that how a nest is constructed does not relate to a role as a receptacle for holding eggs or chicks but rather it is more aligned to the thermal requirements of the bird that built it.

Another paper in Bird Study in 2011 with Chris du Feu of the Treswell Wood Ringing Group (Nottinghamshire) indicated that climate change has altered the breeding patterns of three species but also indicates that great tits mainly hatch all of their eggs but fail to rear all of their chicks whereas Coal Tits mainly have more eggs that fail to hatch and rear all of their chicks.

A review paper came out in Avian Biology Research in 2011 where Charles analysed how different nest types affect the control of humidity around the eggs. Building a cup in a cold climate appeared to have changed the porosity of the eggs in the nest because the good insulation not only keeps out the cold but also keeps in the humidity. To get the correct weight loss during incubation the eggshells have to be relatively more porous.

In May 2012 The Condor, a prestigious US ornithological journal, published a study by Charles, Chris du Feu and another ringer, Joanne Surgey, that described the results of a 10-year study into the use of artificial nest material by tit species in Treswell Wood. Birds use the material depending on how far their nests are from the source of the material.

Finally, Charles has worked with Mark Mainwaring at the University of Lancaster to be the first to show that the effects of temperature on nest mass and insulation in Blue and Great Tits is not a localised phenomenon but is related to temperature across Great Britain; cooler northern temperatures mean that the birds build nests that are heavier and better insulated than individuals of the same species in the warmer south. This important research has just been published and was featured on BBC’s Springwatch earlier this year.

2012 is the sixth year that Charles has been monitoring his nestboxes at Riseholme Park and the fluctuating temperature has hit fledging success. Other current research projects are looking at the data collected in Treswell Wood to ascertain the heritability of the timing of breeding and into the effects of prevailing temperature during nest construction, incubation and rearing on the hatchability of eggs or the fledging success of birds. The team is also looking at the effects of coppice age on reproductive success at Treswell. The long-term goal is to develop a project proposal that will fund the first major study to investigate the factors that determine nest construction behaviour. As part of this Charles is also organising the first international conference on “nest construction and function” that will be held in Lincoln in September 2012 and has already attracted delegates from 11 different countries from around the world.

Charles has been joined this summer by a long-term collaborator Dr Geoff Birchard of George Mason University, near Washington DC, USA. Geoff is spending some of his sabbatical working with Charles on allometric studies to improve our understanding of egg biology.

Charles said: “It’s great to have someone close by to discuss and develop ideas and we hope to sort out a couple of manuscripts over the next couple of months”.