Here are a few options for the WordPress post_tag description, catering to different levels of specificity:

**Option 1: Simple & General**

* **Description:** 屬於日間活動的鳥類，牠們在白天覓食和活動，是觀鳥愛好者常見的對象。 (Shǔyú rìjiān huódòng de niǎolèi, tāmen zài bái tiān mìshí hé huódòng, shì guānniǎo àihǎozhě chángjiàn de duìxiàng.)
* **Translation:** Birds that are active during the day. They forage and move during the daytime, and are common subjects for birdwatchers.

**Option 2: Slightly More Specific**

* **Description:** 指的是在白天活動的鳥類，包括各種雀鳥、猛禽等，其活動模式與夜行性鳥類相反。 (Zhǐ de shì zài bái tiān huódòng de niǎolèi, bāokuò gèzhǒng quèniǎo, měngqín děng, qí huódòng móshì yǔ yèxíngxìng niǎolèi xiāngfǎn.)
* **Translation:** Refers to birds active during the day, including various passerines, birds of prey, etc. Their activity patterns are the opposite of nocturnal birds.

**Option 3: Focusing on Observation**

* **Description:** 標記出在白天觀察到的鳥類物種。瞭解這些鳥類的生活習性，包括牠們覓食、築巢和社交行為。 (Biāojì chū zài bái tiān guānchá dào de niǎolèi wùzhǒng. Liǎojiě zhèxiē niǎolèi de shēnghuó xíxìng, bāokuò tāmen mìshí, zhùcháo hé shèjiāo xíngwéi.)
* **Translation:** Tags the bird species observed during the day. Understand the life habits of these birds, including foraging, nesting, and social behavior.

**Option 4: Technical Focus (If your audience is more knowledgeable)**

* **Description:** 描述日行性鳥類，牠們通常在白天利用視覺及聲音來尋找食物、求偶及溝通，例如：雀形目及猛禽等。 (Miáoshù rìxíngxìng niǎolèi, tāmen tōngcháng zài bái tiān lìyòng shìjué jí shēngyīn lái xúnzhǎo shíwù, qiú’ǒu jí gōutōng, lìrú: Quèxíngmù jí měngqín děng.)
* **Translation:** Describes diurnal birds, which usually use sight and sound to find food, courtship and communication during the day, e.g.: passerines and raptors.

**Which one should you choose?**

* **Consider your audience:** Who are you writing for? Beginner birdwatchers? Experts? Casual readers?
* **Consider the context:** What is the overall tone and purpose of your website or blog?
* **Choose the clearest and most informative option that fits your needs.**

I recommend starting with **Option 2** or **Option 3** as they are good balance of detail and accessibility. Remember to replace the example text in the WordPress tag editor with your chosen description when creating the tag!