WASHINGTON – Employers added an anemic 115,000 jobs in April as a shrinking work force shaved the unemployment rate to 8.1 percent, down slightly from 8.2 percent in March, the government said Friday in a report that’s sure to spark concerns about the economy’s sluggish recovery.

Mainstream forecasters had projected about 170,000 new jobs in April, but they were disappointed for the second consecutive month as a strong winter of hiring due to unseasonable warm weather seems to have moved up job creation.

“The job market was soft in April, given the tepid payroll job gain and the decline in labor force participation. But it isn’t as soft as the data suggest, as it reflects payback from the very warm winter, which juiced up job gains earlier in the year,” said Mark Zandi, the chief economist for forecaster Moody’s Analytics. “Underlying job growth, abstracting from the temporary effects of the weather, is over 175,000 per month. This isn’t boom times, but it is solid enough to bring down unemployment further.”

Part of his optimism came from revisions Friday that showed that hiring in March was 154,000, not 120,000, and that February’s sizzling initial report of 240,000 jobs was actually 259,000. Viewed over a longer stretch, the hiring picture looks stronger than the single month of April.

The White House seized on this theme.

“With upward revisions of 65,000 (private-sector) jobs to the past two months’ employment reports, in the first quarter of 2012 private employment expanded by 697,000 jobs, the largest quarterly increase since the first quarter of 2006,” Alan Krueger, the head of the White House Council of Economic Advisers, said in a statement. “So far this year, 827,000 private-sector jobs have been added, on net.”

Government job losses — on the federal, state and local levels — drag against that number, however. Private-sector employers added 130,000 jobs in April, but the overall number was lower because of the 15,000 government jobs that were lost during the month.

The jobless rate, which fell by a tenth of a percentage point, is declining in part because of workers exiting the labor market.

“The decline in unemployment also reflects the expiration of the emergency unemployment-insurance program in an increasing number of states. Older workers losing unemployment insurance are leaving the work force, contributing to the decline in labor force participation, and younger workers that were slow to take a job now have no choice,” Zandi said. “I expect the job market to reaccelerate later this summer and fall.”