Editing Tree swallow (section)

===Parasites===
[[File:Protocalliphora azurea ? (35372959113).jpg|thumb|Blow-fly in the genus ''Protocalliphora'']]
The tree swallow is vulnerable to various parasites, such as the blood parasite ''[[Trypanosoma]]''. It is also susceptible to the flea ''[[Ceratophyllus idius]]'' and the feather mites ''[[Pteronyssoides tyrrelli]]'', ''[[Trouessartia]]'', and (likely) ''[[Hemialges]]''. It is also probably afflicted by lice of the genera ''[[Brueelia]]'' and ''[[Myrsidea]]''. There is a correlation between the number of fleas on a bird and the number of young it is caring for. This relationship is speculated to arise from an improved microclimate for fleas due to a larger clutch.<ref name="ShutlerMullie2004">{{cite journal|last1=Shutler|first1=Dave|last2=Mullie|first2=Adele|last3=Clark|first3=Robert G|title=Tree swallow reproductive investment, stress, and parasites|journal=Canadian Journal of Zoology|volume=82|issue=3|year=2004|pages=442–448|issn=0008-4301|doi=10.1139/z04-016|bibcode=2004CaJZ...82..442S |citeseerx=10.1.1.530.1736}}</ref> Nestlings also suffer from parasites, like [[blow-fly|blow-flies]] of the genus ''[[Protocalliphora]]'',<ref name="RobyBrink1992"/> which results in a loss of blood by nestlings.<ref name="DeSimoneClotfelter2018">{{cite journal|last1=DeSimone|first1=Joely G.|last2=Clotfelter|first2=Ethan D.|last3=Black|first3=Elizabeth C.|last4=Knutie|first4=Sarah A.|title=Avoidance, tolerance, and resistance to ectoparasites in nestling and adult tree swallows|journal=Journal of Avian Biology|volume=49|issue=2|year=2018|pages=jav–01641|issn=0908-8857|doi=10.1111/jav.01641}}</ref> These parasites, though, are found in a majority of nests and do not seem to have a large effect on nestlings. A study published in 1992 found that the effects of blow-fly parasitism explained only about 5.5% of the variation in nestling mass.<ref name="RobyBrink1992">{{cite journal|last1=Roby|first1=Daniel D.|last2=Brink|first2=Karen L.|last3=Wittmann|first3=Karin|title=Effects of bird blowfly parasitism on eastern bluebird and tree swallow nestlings|journal=Wilson Bulletin|year=1992|volume=104|issue=4|pages=630–643|url=http://sora.unm.edu/sites/default/files/journals/wilson/v104n04/p0630-p0643.pdf}}</ref>