Generate an appropriate single-sentence summary for the given text such that it includes the main topic of the text.

These further infections were identified through contact tracing on Wednesday, taking the overall number of cases to four, the States confirmed. The initial two cases, of "unknown" origin, emerged on Monday and Tuesday, the first not to be connected to inbounded travel since May. Public Health Services said it tested 45 contacts or potential contacts. The States of Guernsey acknowledged the "rumour and speculation online" about the cluster of cases, but was unable to confirm details about the origin. However, a spokeswoman said: "There are clear links between the four cases identified to date, which is extremely helpful in seeking to track, trace and contain the spread of the virus."
Two more Covid-19 infections have been identified in Guernsey in the island's first "cluster" since lockdown.

By Kevin PeacheyPersonal finance reporter Inaccurate and delayed bills were given to business customers after the provider put in a new £40m computer system in 2014, Ofgem said. The penalty will be paid as compensation and in a charity payment. British Gas Business apologised and said good quality customer service had been restored. Compensation Regulator Ofgem said that tens of thousands of customers were left with inaccurate and delayed bills after the new IT billing system was introduced. More than 6,000 new business customers had difficulty in registering with the supplier. There were insufficient staff in place to deal with complaints, Ofgem added. British Gas initially compensated some customers and itself reported the problems to the regulator. It has since hired 350 extra staff to handle the backlog of complaints, and will now pay £9.5m in compensation to micro-business customers (which it will contact directly) and payments to the Money Advice Trust, which runs the Business Debtline. Dermot Nolan, Ofgem chief executive, said: "Ofgem welcomes suppliers investing in new systems and recognises that this can be challenging. However, the £9.5m payment also sends a strong reminder to all energy companies that they must treat consumers fairly at all times, including while new systems are put in place." 'Major undertaking' Gab Barbaro, managing director of British Gas Business, said: "We invested in a new billing system so we could improve the service we provide to our business customers. "At the time, this was a major undertaking - merging nearly 100 different systems into one. It didn't go as smoothly as we would have liked so we reported this to Ofgem as a priority. "We have restored a very good quality of customer service, and more and more of our customers are going online to use the new billing system. I'd like to apologise to our business customers for any inconvenience caused when we were implementing the system." The penalty is smaller than some handed out by Ofgem, such as a £26m fine given to Npower in December 2015 for billing and complaints issues, and an £18m penalty given to Scottish Power in April following IT problems.
British Gas Business will pay a penalty of £9.5m after its customers suffered billing and complaints issues, the energy regulator has said.

By Mark KinverEnvironment reporter, BBC News Researchers say the noise could stop adult birds hearing the hunger calls from their dependent offspring. In their study, the team found that birds nesting in noisy areas were less effective at feeding their chicks as those that nested in quieter places. The findings have been published in the journal Plos One. Scientists from the University of Sheffield reached their conclusion after carrying out a study on Lundy, a 445-hectare (1,100-acre) island located 19km (12mi) off the North Devon coast. Co-author Julia Schroeder explained that the project happened more-or-less by chance. "When I first went to the island, which is very remote and quiet - apart from gulls and shearwaters - I entered a barn and it was very loud," she recalled. The barn contained an electricity generator, yet sparrows were still choosing to nest in the building, so Dr Schroeder wondered whether the conditions affected the songbirds. "I found that there was a reduced fitness - a reduced reproductive output from the nest boxes located in the noisy area," she told BBC News. So she decided to test her findings against classic hypotheses on how noise could affect birds. "The main hypothesis regarding breeding output is that it affects mate choice decisions," she explained. Steep decline However, the study's findings did not fit the existing hypotheses. "In our case, we saw that the birds did not feed the chicks as well as the birds in the quiet area - this was a novel idea that had not been shown before," Dr Schroeder said. "Obviously, chick provision is strongly linked to chick survival because if they do not get fat then they die." Noise seemed to interrupt the communication between the young birds and their parents. "The only difference we found from normal behaviour was in the provisioning behaviour," she observed. "Chicks that were reared in the noisy barn were lighter when they fledged. "So this is why we have said that we think that the provisioning behaviour of females is a factor." Between the mid-1970s and 2008, the UK's sparrow population declined by 71% - with some of the sharpest declines occurring in towns and cities. Dr Schroeder and the team suggested that the noise from the generator on Lundy was comparable to car noise in urban areas. "There are lots of studies on great tits and urban noise, but these tend to focus around mate choice, where the male advertises its quality to the female. "But the idea that the communication between parents and offspring could be affected in cities is fairly new." In 2007, another study by researchers at the University of Sheffield published in Biology Letters found that urban-based robins were choosing to sing and communicate at night in order to avoid noise during the day. Until then, it had been thought that birds were singing at night because they were being disturbed by light pollution. Dr Schroeder added that it could be that other songbird species could also be affected in a similar way as the sparrows on Lundy. She observed: "Many songbirds communicate in a similar way so it is possible that other species could be affected too."

Noise in urban areas could be increasing the mortality rate among young house sparrows, a study has suggested.

