"herrerillo común" meaning in Spanish

{
  "etymology_templates": [
    {
      "args": {
        "1": "es",
        "2": "herrero"
      },
      "expansion": "herrero",
      "name": "m"
    }
  ],
  "etymology_text": "Diminutive of herrero, from the metallic screech of its calls.",
  "forms": [
    {
      "form": "herrerillos comunes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "herrerillo común m (plural herrerillos comunes)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Spanish entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "lifeform",
          "langcode": "es",
          "name": "Birds",
          "orig": "es:Birds",
          "parents": [
            "Vertebrates",
            "Chordates",
            "Animals",
            "Lifeforms",
            "All topics",
            "Life",
            "Fundamental",
            "Nature"
          ],
          "source": "w"
        }
      ],
      "glosses": [
        "blue tit"
      ],
      "id": "en-herrerillo_común-es-noun-hYVQFvls",
      "links": [
        [
          "blue tit",
          "blue tit"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "herrerillo común"
}

{
  "etymology_templates": [
    {
      "args": {
        "1": "es",
        "2": "herrero"
      },
      "expansion": "herrero",
      "name": "m"
    }
  ],
  "etymology_text": "Diminutive of herrero, from the metallic screech of its calls.",
  "forms": [
    {
      "form": "herrerillos comunes",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "m"
      },
      "expansion": "herrerillo común m (plural herrerillos comunes)",
      "name": "es-noun"
    }
  ],
  "lang": "Spanish",
  "lang_code": "es",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "Spanish countable nouns",
        "Spanish entries with incorrect language header",
        "Spanish lemmas",
        "Spanish masculine nouns",
        "Spanish multiword terms",
        "Spanish nouns",
        "es:Birds"
      ],
      "glosses": [
        "blue tit"
      ],
      "links": [
        [
          "blue tit",
          "blue tit"
        ]
      ],
      "tags": [
        "masculine"
      ]
    }
  ],
  "word": "herrerillo común"
}