Urubu vs. abutre
While both abutre and urubu translate to "vulture" in English, the difference lies primarily in biology and geography. Urubu refers to New World vultures found in the Americas, which are very common in Brazil. Abutre refers to Old World vultures found in Europe, Africa, and Asia, though the term is also widely used in Portuguese to describe greedy people metaphorically.
Urubu
B2This word refers to the vultures native to the American continent (New World vultures). In Brazil, urubu is the standard name for the black scavenger bird frequently seen in both cities and rural areas.
O urubu voava alto procurando por alimento na estrada.
(The vulture was flying high looking for food on the road.)
No Brasil, é comum ver um urubu descansando no telhado das casas.
(In Brazil, it is common to see a vulture resting on the roof of houses.)
Eles chamam aquele torcedor de urubu por causa do mascote do time.
(They call that fan a vulture because of the team's mascot.)
A população de urubus ajuda a limpar o meio ambiente.
(The population of vultures helps clean the environment.)
Abutre
C1This word technically refers to the vultures found in Africa, Europe, and Asia (Old World vultures). However, speakers often use abutre metaphorically to describe someone who is greedy, predatory, or exploits the misfortune of others.
Vimos um enorme abutre durante o safári na África.
(We saw a huge vulture during the safari in Africa.)
Aquele advogado é um abutre que lucra com a desgraça alheia.
(That lawyer is a vulture who profits from others' misfortune.)
Os fundos abutres compraram a dívida da empresa falida.
(The vulture funds bought the debt of the bankrupt company.)
O abutre das estepes é uma ave impressionante.
(The steppe vulture is an impressive bird.)
Summary
Use urubu when referring to the actual physical bird found in Brazil or the Americas. Use abutre when referring to birds in Africa/Europe, or when using the word as a metaphor for a greedy person.