The animal charity warned of an increase in the number of pets being put down or waiting to be rehoused as their owners found themselves in financial difficulty. The RSPCA also held its annual awareness week at the end of the month.
Human Rights Watch, which did not feature in last month's table, shot into the second slot after its claim that Saudi Arabia kept women in a state of 'perpetual childhood'.
BBC News reported that, according to the group's latest report, women have to obtain permission from males in order to 'work, travel, marry or even study'. The report noted that 'Saudi women won't make any progress until the government ends the abuses from these misguided policies'.
Amnesty International moved from seventh to third position after igniting debate over the water-boarding torture technique. It released a film in cinemas showing the technique being used at close range.
Director Katie Allen said: 'Our film shows you what the CIA doesn't want you to see - the disgusting reality of half-drowning a person.'
Lawrence Ampofo, a spokesperson for Infonic, which compiles NGO Watch, said: 'Amnesty International demonstrated an extremely well-considered presentation of multi-media campaigning.'
The Red Cross generated coverage after some of its volunteers intervened on ITV's game show Britain's Got Talent. Contestant Nicky Flash's escapology act went wrong and he got stuck inside a duvet while padlocked inside.
Judge Simon Cowell had to call for first-aid help. A Red Cross volunteer was quoted in the Daily Mirror saying: 'I heard Simon shout, "You're first-aiders, aren't you? Go up there and get him out of that bag".'
Meanwhile, The Joseph Rowntree Foundation was thrown into the media spotlight after it published a report concluding that a lack of training was affecting care of the elderly.
NGO WATCH - APRIL 2008 RANKING
Ranking NGO No of mentions
1 RSPCA 181
2 Human Rights Watch 135
3 Amnesty International 132
4 Friends of the Earth 131
5 Cancer Research 126
6 Age Concern 106
7 RSPB 100
8 Red Cross 90
9 Royal British Legion 86
10 Joseph Rowntree Foundation 77