What's Their English Name？? / What are they Called in English? What's Their English Name? / What are they Called in English?

The double-byte question mark looks strange in English.

I thought the name of the birds I saw yesterday by the Taihu Lake was “black-headed gull.” I thought the name of the birds I saw yesterday by Taihu Lake was “black-headed gull.”

Alternative: I thought the birds I saw yesterday by Taihu Lake were called “black-headed gulls.”

I thought the name of the birds I saw yesterday by the Taihu Lake was the black-headed gull. I thought the name of the birds I saw yesterday by the Taihu Lake was the black-headed gull.

I thought the name of the birds I saw yesterday by the Taihu Lake was black-headed gull. I thought the name of the birds I saw yesterday by the Taihu Lake was black-headed gull.

However, I found out their heads are not black. However, I found out their heads are not black.

"found out" means more like it is a new information.

However, I found(later?) {found | realized | noticed} their heads awere not black. However, I (later?) {found | realized | noticed} their heads were not black.

However, I founddiscovered that their heads are not black. However, I discovered that their heads are not black.

However, I found that their heads are not black. However, I found that their heads are not black.

WCould you tell me their English name? Could you tell me their English name?

Using "would" in this question sounds more like that the person knows the answer, but it depends if they feeling like telling you. "Could" is more appropriate, since it's more like asking if the person knows the answer.

And hHere is a picture of them: https://www.youtube.com/post/UgkxEWWfQ0I19PrzxWj4-UU9UlelSdkUlJJ9 Here is a picture of them: https://www.youtube.com/post/UgkxEWWfQ0I19PrzxWj4-UU9UlelSdkUlJJ9