On a side note: Somali ostrich do deserve more conservation attention too.
Masai not so … much!
Somali and Masai are in comparable situations and both (actual Somali, assumed Masai) qualify for Vulnerable under IUCN3.1 A, which incidentally is similar to the argument for treating the lion as Vulnerable. Without going into the long explanations, it basically means that they've declined quite a bit in the last few generations and today they are mainly limited to protected areas such as national parks. Fortunately, there are well-maintained reserves in the ranges of both subspecies, although it appears the Somali is close to disappearing in.... Somalia!
Regardless, both are much safer than the North Africa, which would qualify as Critically Endangered under IUCN3.1 A+C (and likely D+E). Fortunately, there are more in captivity in the Middle East+North Africa than in Europe+North America where numbers still are very low.
North Africa ostriches are the largest aren't they?
That's the widely quoted claim.... the problem is that only in the Southern has a larger number of specimens been weighed/measured. Very few in the others. For example, 20 North African of both sexes weighed 63-104 kg (139-229 lb), but another specimen, the heaviest ostrich on record, weighed 156 kg (344 lb – not 154 kg/340 lb as some sources claim). In comparison, 13 Masai of both sexes weighed 86-145 kg (190-320 lb), and Southern generally weighs 90-130 kg (198-287 lb).
So, do we base "largest" on the single North African record holder (which might be unusually large for the subspecies), or do we base it on the typical weights based on the larger sample of specimens, which still only included 20+13 specimens (a small sample size)? Were these specimens actually typical for the subspecies? Or do we base it on another measurements such as height? In summary, the most accurate answer to North African being largest: Perhaps, but more measurements are necessary to say for certain.