Well, birds generally aren't bad in terms of intelligence, and some of them are very smart - corvids (ravens, magpies etc) have incredibly advanced logical reasoning and use self-modified tools, Harris' hawks have sophisticated pack hunting and social behaviour, parrots have emotional development on par with a young human. Corvids in particular are often placed alongside great apes and cetaceans, they only seem to be lacking on the emotional side - give them a door they'd be physically capable of opening and they'd figure it out pretty quickly.
But no, you can't really assume much about dinosaurs. If you plot the encephalisation quotient (the best means of estimating intelligence based purely on physical remains) of a great white shark on the mammalian scale, it's below pretty much everything, a fraction of even a rabbit. Yet it's proven in the real world to have complex social interactions, advanced navigational ability, flexible hunting strategies for a variety of prey types, variable personality types, and most tellingly, they're very curious.
So, using brain comparisons to estimate intelligence becomes increasingly fuzzy, and eventually wholly erroneous, the further apart the animals are in relationship. This is because brain structure changes enormously through lineages, to cope with the demands of different physiology, different senses, or different lifestyle demands. Bird brains, for example, changed to cope with the demands of flight - the masses of sensory and locomotory data synchronisation they have to throughput to automate that process. Every living bird evolved from a flying ancestor, and they all had the same brain structure - but a structure that non-avian dinosaurs (even those closest to pygostylian birds) are proven to lack. That in itself doesn't necessarily make them any more or less smart, it just means they aren't directly comparable.
And they probably aren't directly comparable to reptiles either, because even the most basal dinosaurs had a greatly higher metabolism than any living reptile, which imposes more regulatory demands on the brain.
It's worth pointing out that Hobson's 1980s study, which assumed dinosaur brains were comparable to reptiles (and it's worth pointing out that most of them do seem similar to reptile brains), found that ceratopsians ranged from slightly below to equal with crocodiles, ornithopods equal or a bit higher, most theropods equal to double. Sauropods and thyreophorans were much lower, as you'd expect from famously "brain the size of a walnut" Stegosaurus.
Deinonychosaurs scored many times higher than crocs, which was the inspiration for Crichton's brainy Velociraptor. But we now know that their brain structure is 30% avian, which puts them in an awkward position of not being directly comparable either to birds, reptiles or other dinosaurs.
Also worth pointing out that the whole validity of EQs and brain-to-body-weight calculations are debated, as intelligence doesn't necessarily scale in direct accordance to cerebrum size, nor *precisely* to body weight (overall cerebral size is sometimes suggested to be a better indicator among primates).
But anyway. If we're talking overall brain size, some dino brains did outsize any bird's. Tyrannosaurus' brain was around a kilogram, larger than a gorilla's.
