"And he took to wife Judith." He went to his own kind, [as it is written] (Leviticus 11:15) "every raven after its kind." In the days of Rabbi Hiyya a starling came to the Land of Israel. They brought it to him and asked: "How shall we tell [whether it is clean or unclean]?" He said to them: "Go and place it on the roof, and whatever bird settles upon it is of its kind." They did so, and this Egyptian raven came and settled beside it. He said to them: "It is unclean," as it is written "every raven after its kind." He said: "Not for nothing did the starling go to the raven, but because it is its kind." So too: just as it is written (Deuteronomy 20:17) "For you shall utterly destroy them," and it is written (Obadiah 1:18) "There shall be no survivor to the house of Esau," "let this one who is destined to be blotted out come and join himself to that one that is destined to be blotted out."
The Starling That Flew to the Raven Because They Were the Same Kind
Yalkut Shimoni on Torah 113:1
וַיִּקַּח אִשָּׁה אֶת יְהוּדִית, הָלַךְ אֵצֶל מִינוֹ "אֶת כָּל עוֹרֵב לְמִינוֹ" בִּימֵי רַבִּי חִיָּא הָלַךְ זַרְזִיר לְאֶרֶץ יִשְׂרָאֵל, אָתוּן טָעוּן לֵיהּ לְגַבֵּיה, אָמְרוּ לוֹ, מַהוּ דְנֵכְלִינֵיה אָמַר לָהֶם אַזְלִין יַהֲבִיתוּן עַל אִגְּרָא, וְכָל עוֹף דִשְׁכוֹן עָלֶיהָ מִינֵיהּ הוּא עַבְדִין כֵּן, וְאָתָא הָדֵין עוּרְבָא מִצְרָאָה וְשָׁכֵן גַבֵּיה אָמַר לוֹן מְסָאָב הוּא דִּכְתִיב (שם) "אֶת כָּל עוֹרֵב לְמִינוֹ" אָמַר לֹא לְחִנָּם הָלַךְ זַרְזִיר אֵצֶל עוֹרֵב אֶלָּא מִפְּנֵי שֶׁהוּא מִינוֹ, כָּךְ לְפִי דִּכְתִיב (דברים כ, יז) "כִּי הַחֲרֵם תַּחְרִימֵם" וּכְתִיב (עובדיה א, יח) "לֹא יִהְיֶה שָׂרִיד לְבֵית עֵשָׂו", יֵיתֵי הָדֵיּן מָחִיק שְׁמֵּא וְיִסֹּב לַהֲּדָא מְחִיקַת שְׁמֵּא.