The real estate sector is higher despite weakness in the share price of Songbird Estates.Docklands office complex Canary Wharf's value increased in the second half of 2009, owner Songbird Estates said today, as it recovered from the collapse of Lehman Brothers, a key tenant.Songbird, which had to raise £1bn in equity and new debt last year to stabilise its position, said the value of its property portfolio at end 2009 had risen by 7.6% to £5bn from June. It is now worth 0.4% less than the end of 2008.Shares are lower overall, but it is defensive sectors such as electricity and pharmaceuticals & biotechnology, which usually perform well when other shares fall, that are among today's worst performers.In the electicity sector, Drax, operator of the UK's largest coal-fired power station, and Scottish and Southern Energy are lower, while sector giants AstraZeneca and GlaxoSmithKline weigh on the pharma sector.Top performing sectors so far todayIndustrial Metals & Mining 6,697.57 +1.99%Real Estate Investment & Services 1,579.32 +1.74%Automobiles & Parts 3,231.21 +1.39%Real Estate Investment Trusts 1,920.26 +1.17%Alternative Energy 6,124.94 +0.99%Bottom performing sectors so far todayElectricity 6,420.03 -2.41%Forestry & Paper 4,973.14 -1.60%Pharmaceuticals & Biotechnology 8,972.25 -1.05%Banks 5,190.89 -0.67%Gas, Water & Multiutilities 4,187.25 -0.64%