Navigation Links
Hormones dictate when youngsters fly the nest, says new research

Seabirds feed their young less as they reach an age to fly the nest, but it's hormones that actually control when the chicks leave home, according to new research from the University of Leeds.

The study published online in Behavioural Ecology today (05 July) aimed to pinpoint the main trigger which causes chicks to leave the nest and embark on an independent life, a process known as fledging.

While studying a colony of Manx Shearwaters (Puffinus puffinus), on the island of Skomer, researchers from the University's Faculty of Biological Sciences noticed that parent birds seemed to become increasingly insensitive to their chicks' demands for food as they grew close to fledging. At the same time the chicks showed a marked increase in levels of the hormone corticosterone. However, the team needed to know whether this increase was independent of, or caused by, the reduction in feeding.

They decided to trick the parent birds, by swapping chicks of different ages between nests which the birds make in burrows in the ground to see how this affected both parental care and the time chicks took to fledge.

"Manx Shearwaters don't recognise their own offspring, but will simply go back to the same nest after they've gathered food. They have one chick, which makes the interactions between parent and offspring easier to study," explains lead researcher, Dr Keith Hamer. "We swapped chicks which were between 10 days and two weeks apart in age, to see what impact it would have. We wanted to find out whether parents and chicks were responding to each other's behaviour, or whether each was acting independently."

The team discovered that adults reduced their food provisioning after about 60 days of raising a chick, regardless of the chick's stage of development. Although females more than males will adjust their feeding levels to how much their chicks beg for food, after around 60 days both parents start to ignore their pleas. This held true whether parents were feeding their own chicks, or foster-chicks of different ages.

The surge in corticosterone took place over the final few weeks before chicks fledged at about 70 days of age. This held true even when chicks had been fostered by parents at a different stage of the feeding cycle, so was clearly independent of the parent's behaviour and any reduction in food.

"Our findings show that young Manx Shearwaters leave home of their own accord when their corticosterone levels have reached a peak rather than as a result of changes in parental behaviour," says Dr Hamer. "Both parents and chicks need large energy reserves for their arduous migration across the Atlantic to South and Central America, and parents seem to reduce how much they feed their young simply to protect themselves."

"Unlike some other bird species, which let their offspring dictate the level of care, seabirds appear to weigh up the cost of a chick fledging underweight against the greater cost of losing the chance to breed again," he adds. "Manx Shearwaters have a breeding life of around forty years, so parents pay a high cost if they end the season too weak to complete their own migration."


Contact: Dr. Keith Hamer
University of Leeds

Related biology news :

1. BRG1 mutations confer resistance to hormones in lung cancer
2. Study by UC Santa Barbara researchers suggests that bacteria communicate by touch
3. Research reveals first evidence of hunting by prehistoric Ohioans
4. Diabetes Research Institute develops oxygen-generating biomaterial
5. APS issues new policy requiring identification of sex or gender in reporting scientific research
6. UC Santa Barbara researchers discover genetic link between visual pathways of hydras and humans
7. Study jointly led by UCSB researcher supports theory of extraterrestrial impact
8. U of Alberta researcher steps closer to understand autoimmune diseases
9. Research on flavanols and procyanidins provides new insights into how these phytonutrients may positively impact human health
10. A project to research biological and chemical aspects of microalgae to fuel approach
11. Scripps Research discoveries lead to newly approved drug for infant respiratory distress syndrome
Post Your Comments:
Related Image:
Hormones dictate when youngsters fly the nest, says new research
(Date:10/29/2015)... , October 29, 2015 ... biometric authentication company focused on the growing mobile ... wallet announces that StackCommerce, a leading marketplace to ... featuring the Wocket® smart wallet on StackSocial for ... ) ("NXT-ID" or the "Company"), a biometric authentication ...
(Date:10/27/2015)... JOSE, Calif. , Oct. 27, 2015 Synaptics ... interface solutions, today announced that Google has adopted the ... of touch controller solutions to power its newest flagship ... 6P by Huawei. --> ... partners like Google to provide strategic collaboration in the ...
(Date:10/23/2015)... Research and Markets ( ) has ... Biometrics Market 2015-2019" report to their offering. ... global voice recognition biometrics market to grow at a ... --> --> The report, Global Voice ... an in-depth market analysis with inputs from industry experts. ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... Nov. 24, 2015 Cepheid (NASDAQ: CPHD ... at the following conference, and invited investors to participate ...      Tuesday, December 1, 2015 at 11.00 a.m. ...      Tuesday, December 1, 2015 at 11.00 a.m. ... New York, NY      Tuesday, December ...
(Date:11/24/2015)... ... 24, 2015 , ... International Society for Pharmaceutical Engineering (ISPE) ... annual events for pharmaceutical manufacturing: 2015 Annual Meeting. The conference took place in ... largest number of attendees in more than a decade. , “The 2015 ...
(Date:11/24/2015)... , ... November 24, 2015 , ... This fall, global ... competitive events in five states to develop and pitch their BIG ideas to improve ... each state are competing for votes to win the title of SAP's Teen Innovator, ...
(Date:11/24/2015)... 24, 2015  Tikcro Technologies Ltd. (OTCQB: TIKRF) today announced that its ... at 11:00 a.m. Israel time, at the law ... Allon Street, 36 th Floor, Tel Aviv, Israel ... and Izhak Tamir to the Board of Directors; ... directors; , approval of an amendment to certain terms of options ...
Breaking Biology Technology: